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Coordinate systems for the hyperbolic plane

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2345: 1258: 2337: 769: 3129: 63: 502: 764:{\displaystyle {\begin{aligned}\left.{\frac {\mathrm {d} }{\mathrm {d} {\theta }}}\operatorname {dist} (\langle r,\theta _{1}\rangle ,\langle r,\theta _{1}+\theta \rangle )\right|_{\theta =0}&=\left.{\frac {\mathrm {d} }{\mathrm {d} {\theta }}}\operatorname {arcosh} \,\left(\cosh ^{2}r-\sinh ^{2}r\cos(\theta )\right)\right|_{\theta =0}\\&=\sinh(r)\end{aligned}}} 369: 4049: 2600: 4090:
traditionally is concerned with Euclidean geometry, but triangle centers can also be studied in hyperbolic geometry. Using gyrotrigonometry, expressions for trigonometric barycentric coordinates can be calculated that have the same form for both euclidean and hyperbolic geometry. In order for the
161: 3787: 3118: 3672: 2051: 997: 2390: 2316: 883: 2713: 2819: 1940: 364:{\displaystyle \operatorname {dist} (\langle r_{1},\theta _{1}\rangle ,\langle r_{2},\theta _{2}\rangle )=\operatorname {arcosh} \,\left(\cosh r_{1}\cosh r_{2}-\sinh r_{1}\sinh r_{2}\cos(\theta _{2}-\theta _{1})\right)\,.} 4044:{\displaystyle \left({\frac {\tanh x_{a}}{\sqrt {1-\tanh ^{2}x_{a}-\tanh ^{2}y_{a}}}}\ ,\ {\frac {\tanh y_{a}}{\sqrt {1-\tanh ^{2}x_{a}-\tanh ^{2}y_{a}}}}\ ,\ {\frac {1}{\sqrt {1-\tanh ^{2}x_{a}-\tanh ^{2}y_{a}}}}\right)} 1753: 1672: 2943: 2891: 1866: 1814: 494: 3001: 450: 3495: 2995: 1490: 3464: 2595:{\displaystyle \operatorname {dist} (\langle x_{1},y_{1}\rangle ,\langle x_{2},y_{2}\rangle )=\operatorname {arcosh} \left(\cosh y_{1}\cosh(x_{2}-x_{1})\cosh y_{2}-\sinh y_{1}\sinh y_{2}\right)\,.} 1946: 1354: 893: 507: 2117: 3758: 2384:
will be the distance along the perpendicular of the given point from its foot (positive on one side and negative on the other). Then the distance between two such points will be
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of the quadrant. Due to the study of ratios in physics and economics where the quadrant is the universe of discourse, its points are said to be located by
2732: 1872: 1681: 1600: 4204:, Abraham A. Ungar, The Australian Journal of Mathematical Analysis and Applications, AJMAA, Volume 6, Issue 1, Article 18, pp. 1–35, 2009 2344: 3113:{\displaystyle \theta =2\operatorname {arctan} \,\left({\frac {\sinh y}{\sinh x\cosh y+{\sqrt {\cosh ^{2}x\cosh ^{2}y-1}}}}\right)\,.} 2897: 2845: 1820: 1768: 3667:{\displaystyle x_{p}={\frac {x_{b}}{1+{\sqrt {1-x_{b}^{2}-y_{b}^{2}}}}},\ \ y_{p}={\frac {y_{b}}{1+{\sqrt {1-x_{b}^{2}-y_{b}^{2}}}}}} 455: 1257: 377: 2356:-axis) in the hyperbolic plane (with a standardized curvature of -1) and label the points on it by their distance from an origin ( 2949: 4228: 2046:{\displaystyle \theta =2\operatorname {arctan} \,\left({\frac {\tanh y}{\tanh x+{\sqrt {\tanh ^{2}x+\tanh ^{2}y}}}}\right)\,.} 1411: 4186: 4138: 3376: 992:{\displaystyle \theta =\theta _{0}\pm {\frac {\pi }{2}}\quad {\text{ or }}\quad \tanh r=\tanh r_{0}\sec(\theta -\theta _{0})} 2311:{\displaystyle x_{l}=x_{a}\ ,\ \tanh(y_{l})=\tanh(y_{a})\cosh(x_{a})\ ,\ \tanh(y_{a})={\frac {\tanh(y_{l})}{\cosh(x_{l})}}} 1275: 2111:
is the distance along the perpendicular of the given point to its foot (positive on one side and negative on the other).
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The relationship of Lobachevsky coordinates to polar coordinates (assuming the origin is the pole and that the positive
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of the Poincaré model carry over to the quadrant; in particular the left or right shifts of the real axis correspond to
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This article tries to give an overview of several coordinate systems in use for the two-dimensional hyperbolic plane.
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There are however different coordinate systems for hyperbolic plane geometry. All are based on choosing a real (non
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The Weierstrass coordinates of a point are the Cartesian coordinates of the point when the point is mapped in the
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The relationship of axial coordinates to polar coordinates (assuming the origin is the pole and that the positive
152: 3356: 1128:) in the upper half-plane. The hyperbolic metric in the quadrant depends on the Poincaré half-plane metric. The 3474:
The Poincaré coordinates of a point are the Cartesian coordinates of the point when the point is mapped in the
2364:-axis (positive on one side and negative on the other). For any point in the plane, one can define coordinates 2348:
Circles about the points (0,0), (0,1), (0,2) and (0,3) of radius 3.5 in the Lobachevsky hyperbolic coordinates.
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The Lobachevsky coordinates are useful for integration for length of curves and area between lines and curves.
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do not exist. The sum of the angles of a quadrilateral in hyperbolic geometry is always less than 4
1047: 28:. Several qualitatively different ways of coordinatizing the plane in hyperbolic geometry are used. 3340: 2606: 2330: 2326: 1133: 102: 98: 47: 43: 39: 17: 878:{\displaystyle (\mathrm {d} s)^{2}=(\mathrm {d} r)^{2}+\sinh ^{2}r\,(\mathrm {d} \theta )^{2}\,.} 35: 4130: 62: 4178: 4182: 4134: 3683: 1129: 94: 4081: 4070: 1078: 3287: 3260: 3213: 3163: 4232: 4087: 21: 4201: 2340:
Circles about the origin of radius 1, 5 and 10 in the Lobachevsky hyperbolic coordinates.
2708:{\displaystyle (\mathrm {d} s)^{2}=\cosh ^{2}y\,(\mathrm {d} x)^{2}+(\mathrm {d} y)^{2}} 4171: 4123: 3314: 3240: 3190: 3139: 1042: 125: 4245: 4226:
Barycentric Calculus In Euclidean And Hyperbolic Geometry: A Comparative Introduction
4225: 775: 2814:{\displaystyle \tanh y=A\cosh x+B\sinh x\quad {\text{ when }}\quad A^{2}<1+B^{2}} 2096:-axis to the origin (positive on one side and negative on the other, the same as in 74:. In green, the point with radial coordinate 3 and angular coordinate 60 degrees or 3343:
and take the Euclidean coordinates inside the model as the hyperbolic coordinates.
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have axial coordinates, but not every pair of real numbers corresponds to a point.
1241:-axis to the origin (regarded as positive on one side and negative on the other); 1935:{\displaystyle r=\operatorname {artanh} \,({\sqrt {\tanh ^{2}x+\tanh ^{2}y}}\,)} 1266: 1168: 1153: 25: 1220:, the coordinates are found by dropping perpendiculars from the point onto the 4065: 3208: 1149: 3691: 3157: 2352:
Construct a Cartesian-like coordinate system as follows. Choose a line (the
1748:{\displaystyle \operatorname {artanh} \left(\tanh(x_{a})\cosh(y_{a})\right)} 1667:{\displaystyle \operatorname {artanh} \left(\tanh(y_{a})\cosh(x_{a})\right)} 155:, we get that the distance between two points given in polar coordinates is 91: 2718:
In this coordinate system, straight lines are either perpendicular to the
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is closely related to a model of the hyperbolic plane in the quadrant
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The Poincaré coordinates, in terms of the Beltrami coordinates, are:
1160:). Also in hyperbolic geometry there are no equidistant lines (see 3127: 2343: 2335: 1256: 1013:
are the coordinates of the nearest point on the line to the pole.
110: 4129:(Corrected 4. print. ed.). New York, NY: Springer. pp.  4095:
encapsulate the specification of the anglesum being 180 degrees.
2938:{\displaystyle y=\operatorname {arsinh} \,(\sinh r\sin \theta )} 2886:{\displaystyle x=\operatorname {artanh} \,(\tanh r\cos \theta )} 1861:{\displaystyle y=\operatorname {artanh} \,(\tanh r\sin \theta )} 1809:{\displaystyle x=\operatorname {artanh} \,(\tanh r\cos \theta )} 3486:
and the origin is mapped to the centre of the boundary circle.
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and the origin is mapped to the centre of the boundary circle.
489:{\displaystyle {\frac {\mathrm {d} }{\mathrm {d} {\theta }}}=0} 4214:
Hyperbolic Triangle Centers: The Special Relativistic Approach
445:{\displaystyle r=r_{1}=r_{2},\theta =\theta _{2}-\theta _{1}} 3136:
Another coordinate system represents each hyperbolic point
2990:{\displaystyle r=\operatorname {arcosh} \,(\cosh x\cosh y)} 627: 512: 2832:
are real parameters which characterize the straight line.
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is the distance from the foot of the perpendicular to the
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is the distance from the foot of the perpendicular on the
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is the distance from the foot of the perpendicular on the
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The straight lines are described by equations of the form
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Circles about the origin in hyperbolic axial coordinates.
1485:{\displaystyle \tanh ^{2}(x_{a})+\tanh ^{2}(y_{a})>1} 4125:
The foundations of geometry and the non-Euclidean plane
3459:{\displaystyle x_{b}=\tanh(x_{a}),\ y_{b}=\tanh(y_{a})} 1164:). This all has influences on the coordinate systems. 3790: 3699: 3498: 3379: 3317: 3290: 3263: 3243: 3216: 3193: 3166: 3142: 3004: 2952: 2900: 2848: 2735: 2618: 2393: 2120: 1949: 1875: 1823: 1771: 1684: 1603: 1550: 1498: 1414: 1362: 1349:{\displaystyle \tanh ^{2}(x_{a})+\tanh ^{2}(y_{a})=1} 1278: 1086: 1050: 896: 784: 505: 458: 380: 164: 3237:
along the horocycle between a fixed reference point
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by two real numbers, defined relative to some given
2726:= a constant) or described by equations of the form 2605:
This formula can be derived from the formulas about
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will be the label of the foot of the perpendicular.
4170: 4122: 4043: 3752: 3666: 3458: 3323: 3303: 3276: 3249: 3229: 3199: 3179: 3148: 3112: 2989: 2937: 2885: 2813: 2707: 2594: 2310: 2045: 1934: 1860: 1808: 1747: 1666: 1585: 1533: 1484: 1397: 1348: 1116: 1069: 991: 877: 763: 488: 444: 363: 116:The reference point (analogous to the origin of a 4116: 4114: 4112: 4110: 4108: 128:from the pole in the reference direction is the 66:Points in the polar coordinate system with pole 3760:and the origin is mapped to the point (0,0,1). 3753:{\displaystyle (t\ ,\ 0\ ,\ {\sqrt {t^{2}+1}})} 2079:are found by dropping a perpendicular onto the 24:, each point can be uniquely identified by two 4091:expressions to coincide, the expressions must 3339:Model-based coordinate systems use one of the 3355:of the point when the point is mapped in the 8: 4169:Ramsay, Arlan; Richtmyer, Robert D. (1995). 3351:The Beltrami coordinates of a point are the 3160:. These numbers are the hyperbolic distance 2461: 2435: 2429: 2403: 595: 570: 564: 545: 232: 206: 200: 174: 132:. The distance from the pole is called the 1179:-axis) and after that many choices exist. 4027: 4014: 4001: 3988: 3972: 3954: 3941: 3928: 3915: 3897: 3884: 3866: 3853: 3840: 3827: 3809: 3796: 3789: 3733: 3727: 3698: 3653: 3648: 3635: 3630: 3618: 3605: 3599: 3590: 3566: 3561: 3548: 3543: 3531: 3518: 3512: 3503: 3497: 3447: 3425: 3406: 3384: 3378: 3316: 3311:is the closest point on the horocycle to 3295: 3289: 3268: 3262: 3242: 3221: 3215: 3192: 3171: 3165: 3141: 3106: 3079: 3063: 3057: 3022: 3017: 3003: 2962: 2951: 2910: 2899: 2858: 2847: 2805: 2786: 2776: 2734: 2699: 2687: 2675: 2663: 2659: 2647: 2634: 2622: 2617: 2588: 2577: 2561: 2542: 2523: 2510: 2491: 2455: 2442: 2423: 2410: 2392: 2296: 2272: 2256: 2244: 2213: 2191: 2166: 2138: 2125: 2119: 2039: 2018: 1999: 1993: 1967: 1962: 1948: 1928: 1914: 1895: 1889: 1885: 1874: 1833: 1822: 1781: 1770: 1731: 1709: 1683: 1650: 1628: 1602: 1574: 1561: 1549: 1522: 1509: 1497: 1467: 1451: 1435: 1419: 1413: 1386: 1373: 1361: 1331: 1315: 1299: 1283: 1277: 1104: 1099: 1085: 1057: 1049: 980: 955: 927: 916: 907: 895: 871: 865: 853: 849: 837: 824: 812: 800: 788: 783: 720: 683: 664: 654: 643: 638: 632: 630: 606: 583: 558: 528: 523: 517: 515: 506: 504: 472: 467: 461: 459: 457: 436: 423: 404: 391: 379: 357: 343: 330: 311: 295: 276: 260: 244: 226: 213: 194: 181: 163: 2325:Lobachevsky coordinates are named after 61: 4235:, Abraham Ungar, World Scientific, 2010 4104: 34:In the descriptions below the constant 4177:. New York: Springer-Verlag. pp.  2097: 2372:by dropping a perpendicular onto the 7: 3763:The point P with axial coordinates ( 2612:The corresponding metric tensor is: 4173:Introduction to hyperbolic geometry 3207:to the horocycle, and the (signed) 1117:{\displaystyle u=\ln {\sqrt {x/y}}} 4202:Hyperbolic Barycentric Coordinates 4076:Hyperbolic barycentric coordinates 2688: 2664: 2623: 1144:Cartesian-style coordinate systems 854: 813: 789: 639: 633: 524: 518: 468: 462: 14: 4082:Gyrovector space#Triangle centers 3132:Horocycle-based coordinate system 3124:Horocycle-based coordinate system 1175:) on a chosen directed line (the 4216:, Abraham Ungar, Springer, 2010 3482:-axis is mapped to the segment 3363:-axis is mapped to the segment 2781: 2775: 932: 926: 4158:. Moscow: Mir. pp. 64–68. 3747: 3700: 3690:-axis is mapped to the (half) 3453: 3440: 3412: 3399: 3370:The following equations hold: 3335:Model-based coordinate systems 2984: 2963: 2932: 2911: 2880: 2859: 2696: 2684: 2672: 2660: 2631: 2619: 2529: 2503: 2464: 2400: 2302: 2289: 2278: 2265: 2250: 2237: 2219: 2206: 2197: 2184: 2172: 2159: 1929: 1886: 1855: 1834: 1803: 1782: 1737: 1724: 1715: 1702: 1656: 1643: 1634: 1621: 1586:{\displaystyle P(x_{a},y_{a})} 1580: 1554: 1534:{\displaystyle P(x_{a},y_{a})} 1528: 1502: 1473: 1460: 1441: 1428: 1398:{\displaystyle P(x_{a},y_{a})} 1392: 1366: 1337: 1324: 1305: 1292: 1070:{\displaystyle v={\sqrt {xy}}} 1041:> 0}. For such a point the 986: 967: 862: 850: 821: 809: 797: 785: 754: 748: 707: 701: 598: 542: 349: 323: 235: 171: 140:, and the angle is called the 109:from a reference point and an 1: 4154:Smorgorzhevsky, A.S. (1982). 3686:of the hyperbolic plane, the 3478:of the hyperbolic plane, the 3359:of the hyperbolic plane, the 3341:models of hyperbolic geometry 2839:-axis is the polar axis) is 2061:The Lobachevsky coordinates 1762:-axis is the polar axis) is 1205:are found by constructing a 113:from a reference direction. 1218:Cartesian coordinate system 1209:-axis perpendicular to the 4273: 4121:Martin, George E. (1998). 4063: 2329:one of the discoverers of 1213:-axis through the origin. 1023:Poincaré half-plane model 774:we get the corresponding 153:hyperbolic law of cosines 38:of the plane is −1. 1544:The distance of a point 3678:Weierstrass coordinates 2057:Lobachevsky coordinates 1541:is not a point at all. 1148:In hyperbolic geometry 88:polar coordinate system 58:Polar coordinate system 4156:Lobachevskian geometry 4060:Gyrovector coordinates 4045: 3754: 3668: 3460: 3325: 3305: 3278: 3251: 3231: 3201: 3181: 3150: 3133: 3114: 2991: 2939: 2887: 2815: 2709: 2596: 2349: 2341: 2312: 2047: 1936: 1862: 1810: 1749: 1668: 1587: 1535: 1486: 1399: 1350: 1262: 1138:hyperbolic coordinates 1118: 1071: 993: 879: 765: 490: 446: 365: 83: 4046: 3755: 3669: 3461: 3353:Cartesian coordinates 3326: 3306: 3304:{\displaystyle P_{h}} 3279: 3277:{\displaystyle P_{h}} 3252: 3232: 3230:{\displaystyle y_{h}} 3202: 3182: 3180:{\displaystyle x_{h}} 3151: 3131: 3115: 2992: 2940: 2888: 2816: 2722:-axis (with equation 2710: 2597: 2347: 2339: 2313: 2048: 1937: 1863: 1811: 1750: 1669: 1588: 1536: 1487: 1400: 1351: 1265:Every point and most 1260: 1254:-axis to the origin. 1158:Lambert quadrilateral 1119: 1072: 1017:Quadrant model system 994: 880: 766: 491: 452:, differentiating at 447: 366: 78:. In blue, the point 65: 3788: 3697: 3496: 3470:Poincaré coordinates 3377: 3357:Beltrami–Klein model 3347:Beltrami coordinates 3315: 3288: 3261: 3241: 3214: 3191: 3164: 3140: 3002: 2950: 2898: 2846: 2733: 2616: 2607:hyperbolic triangles 2391: 2118: 1947: 1873: 1821: 1769: 1682: 1601: 1548: 1496: 1412: 1360: 1276: 1134:hyperbolic rotations 1084: 1048: 894: 782: 503: 456: 378: 162: 52:hyperbolic functions 4252:Hyperbolic geometry 3658: 3640: 3571: 3553: 3476:Poincaré disk model 2331:hyperbolic geometry 2327:Nikolai Lobachevsky 1405:is an ideal point. 105:is determined by a 4257:Coordinate systems 4231:2012-05-19 at the 4041: 3750: 3664: 3644: 3626: 3557: 3539: 3456: 3321: 3301: 3274: 3247: 3227: 3197: 3177: 3146: 3134: 3110: 2987: 2935: 2883: 2811: 2705: 2592: 2350: 2342: 2308: 2043: 1932: 1858: 1806: 1745: 1664: 1583: 1531: 1482: 1395: 1346: 1263: 1187:Axial coordinates 1114: 1067: 989: 875: 761: 759: 486: 442: 361: 142:angular coordinate 84: 36:Gaussian curvature 4034: 4033: 3971: 3965: 3961: 3960: 3883: 3877: 3873: 3872: 3745: 3726: 3720: 3714: 3708: 3684:hyperboloid model 3662: 3659: 3585: 3582: 3575: 3572: 3420: 3324:{\displaystyle P} 3250:{\displaystyle O} 3200:{\displaystyle P} 3149:{\displaystyle P} 3100: 3097: 2779: 2360:=0) point on the 2306: 2230: 2224: 2152: 2146: 2098:axial coordinates 2033: 2030: 1926: 1183:Axial coordinates 1124:produce a point ( 1112: 1065: 930: 924: 649: 534: 478: 134:radial coordinate 95:coordinate system 4264: 4236: 4223: 4217: 4211: 4205: 4199: 4193: 4192: 4176: 4166: 4160: 4159: 4151: 4145: 4144: 4128: 4118: 4088:triangle centers 4071:Gyrovector space 4050: 4048: 4047: 4042: 4040: 4036: 4035: 4032: 4031: 4019: 4018: 4006: 4005: 3993: 3992: 3977: 3973: 3969: 3963: 3962: 3959: 3958: 3946: 3945: 3933: 3932: 3920: 3919: 3904: 3903: 3902: 3901: 3885: 3881: 3875: 3874: 3871: 3870: 3858: 3857: 3845: 3844: 3832: 3831: 3816: 3815: 3814: 3813: 3797: 3759: 3757: 3756: 3751: 3746: 3738: 3737: 3728: 3724: 3718: 3712: 3706: 3673: 3671: 3670: 3665: 3663: 3661: 3660: 3657: 3652: 3639: 3634: 3619: 3610: 3609: 3600: 3595: 3594: 3583: 3580: 3576: 3574: 3573: 3570: 3565: 3552: 3547: 3532: 3523: 3522: 3513: 3508: 3507: 3485: 3465: 3463: 3462: 3457: 3452: 3451: 3430: 3429: 3418: 3411: 3410: 3389: 3388: 3366: 3330: 3328: 3327: 3322: 3310: 3308: 3307: 3302: 3300: 3299: 3283: 3281: 3280: 3275: 3273: 3272: 3256: 3254: 3253: 3248: 3236: 3234: 3233: 3228: 3226: 3225: 3206: 3204: 3203: 3198: 3186: 3184: 3183: 3178: 3176: 3175: 3155: 3153: 3152: 3147: 3119: 3117: 3116: 3111: 3105: 3101: 3099: 3098: 3084: 3083: 3068: 3067: 3058: 3034: 3023: 2996: 2994: 2993: 2988: 2944: 2942: 2941: 2936: 2892: 2890: 2889: 2884: 2820: 2818: 2817: 2812: 2810: 2809: 2791: 2790: 2780: 2778: when  2777: 2714: 2712: 2711: 2706: 2704: 2703: 2691: 2680: 2679: 2667: 2652: 2651: 2639: 2638: 2626: 2601: 2599: 2598: 2593: 2587: 2583: 2582: 2581: 2566: 2565: 2547: 2546: 2528: 2527: 2515: 2514: 2496: 2495: 2460: 2459: 2447: 2446: 2428: 2427: 2415: 2414: 2317: 2315: 2314: 2309: 2307: 2305: 2301: 2300: 2281: 2277: 2276: 2257: 2249: 2248: 2228: 2222: 2218: 2217: 2196: 2195: 2171: 2170: 2150: 2144: 2143: 2142: 2130: 2129: 2052: 2050: 2049: 2044: 2038: 2034: 2032: 2031: 2023: 2022: 2004: 2003: 1994: 1979: 1968: 1941: 1939: 1938: 1933: 1927: 1919: 1918: 1900: 1899: 1890: 1867: 1865: 1864: 1859: 1815: 1813: 1812: 1807: 1754: 1752: 1751: 1746: 1744: 1740: 1736: 1735: 1714: 1713: 1673: 1671: 1670: 1665: 1663: 1659: 1655: 1654: 1633: 1632: 1592: 1590: 1589: 1584: 1579: 1578: 1566: 1565: 1540: 1538: 1537: 1532: 1527: 1526: 1514: 1513: 1491: 1489: 1488: 1483: 1472: 1471: 1456: 1455: 1440: 1439: 1424: 1423: 1404: 1402: 1401: 1396: 1391: 1390: 1378: 1377: 1355: 1353: 1352: 1347: 1336: 1335: 1320: 1319: 1304: 1303: 1288: 1287: 1123: 1121: 1120: 1115: 1113: 1108: 1100: 1079:hyperbolic angle 1076: 1074: 1073: 1068: 1066: 1058: 998: 996: 995: 990: 985: 984: 960: 959: 931: 928: 925: 917: 912: 911: 884: 882: 881: 876: 870: 869: 857: 842: 841: 829: 828: 816: 805: 804: 792: 770: 768: 767: 762: 760: 735: 731: 730: 719: 715: 714: 710: 688: 687: 669: 668: 650: 648: 647: 642: 636: 631: 617: 616: 605: 601: 588: 587: 563: 562: 535: 533: 532: 527: 521: 516: 495: 493: 492: 487: 479: 477: 476: 471: 465: 460: 451: 449: 448: 443: 441: 440: 428: 427: 409: 408: 396: 395: 370: 368: 367: 362: 356: 352: 348: 347: 335: 334: 316: 315: 300: 299: 281: 280: 265: 264: 231: 230: 218: 217: 199: 198: 186: 185: 120:) is called the 118:Cartesian system 81: 77: 18:hyperbolic plane 4272: 4271: 4267: 4266: 4265: 4263: 4262: 4261: 4242: 4241: 4240: 4239: 4233:Wayback Machine 4224: 4220: 4212: 4208: 4200: 4196: 4189: 4168: 4167: 4163: 4153: 4152: 4148: 4141: 4120: 4119: 4106: 4101: 4078: 4068: 4062: 4057: 4023: 4010: 3997: 3984: 3950: 3937: 3924: 3911: 3893: 3886: 3862: 3849: 3836: 3823: 3805: 3798: 3795: 3791: 3786: 3785: 3781:) is mapped to 3780: 3771: 3729: 3695: 3694: 3680: 3611: 3601: 3586: 3524: 3514: 3499: 3494: 3493: 3483: 3472: 3443: 3421: 3402: 3380: 3375: 3374: 3364: 3349: 3337: 3313: 3312: 3291: 3286: 3285: 3264: 3259: 3258: 3239: 3238: 3217: 3212: 3211: 3189: 3188: 3167: 3162: 3161: 3138: 3137: 3126: 3075: 3059: 3035: 3024: 3018: 3000: 2999: 2948: 2947: 2896: 2895: 2844: 2843: 2801: 2782: 2731: 2730: 2695: 2671: 2643: 2630: 2614: 2613: 2573: 2557: 2538: 2519: 2506: 2487: 2480: 2476: 2451: 2438: 2419: 2406: 2389: 2388: 2292: 2282: 2268: 2258: 2240: 2209: 2187: 2162: 2134: 2121: 2116: 2115: 2110: 2091: 2078: 2069: 2059: 2014: 1995: 1980: 1969: 1963: 1945: 1944: 1910: 1891: 1871: 1870: 1819: 1818: 1767: 1766: 1727: 1705: 1695: 1691: 1680: 1679: 1646: 1624: 1614: 1610: 1599: 1598: 1570: 1557: 1546: 1545: 1518: 1505: 1494: 1493: 1463: 1447: 1431: 1415: 1410: 1409: 1382: 1369: 1358: 1357: 1327: 1311: 1295: 1279: 1274: 1273: 1249: 1236: 1204: 1195: 1185: 1146: 1082: 1081: 1046: 1045: 1019: 1012: 1008: 976: 951: 903: 892: 891: 861: 833: 820: 796: 780: 779: 758: 757: 733: 732: 679: 660: 659: 655: 637: 629: 626: 625: 618: 579: 554: 522: 514: 511: 510: 501: 500: 466: 454: 453: 432: 419: 400: 387: 376: 375: 339: 326: 307: 291: 272: 256: 249: 245: 222: 209: 190: 177: 160: 159: 92:two-dimensional 79: 75: 70:and polar axis 60: 22:Euclidean plane 12: 11: 5: 4270: 4268: 4260: 4259: 4254: 4244: 4243: 4238: 4237: 4218: 4206: 4194: 4187: 4161: 4146: 4139: 4103: 4102: 4100: 4097: 4077: 4074: 4064:Main article: 4061: 4058: 4056: 4053: 4052: 4051: 4039: 4030: 4026: 4022: 4017: 4013: 4009: 4004: 4000: 3996: 3991: 3987: 3983: 3980: 3976: 3968: 3957: 3953: 3949: 3944: 3940: 3936: 3931: 3927: 3923: 3918: 3914: 3910: 3907: 3900: 3896: 3892: 3889: 3880: 3869: 3865: 3861: 3856: 3852: 3848: 3843: 3839: 3835: 3830: 3826: 3822: 3819: 3812: 3808: 3804: 3801: 3794: 3776: 3767: 3749: 3744: 3741: 3736: 3732: 3723: 3717: 3711: 3705: 3702: 3679: 3676: 3675: 3674: 3656: 3651: 3647: 3643: 3638: 3633: 3629: 3625: 3622: 3617: 3614: 3608: 3604: 3598: 3593: 3589: 3579: 3569: 3564: 3560: 3556: 3551: 3546: 3542: 3538: 3535: 3530: 3527: 3521: 3517: 3511: 3506: 3502: 3484:(−1,0) − (1,0) 3471: 3468: 3467: 3466: 3455: 3450: 3446: 3442: 3439: 3436: 3433: 3428: 3424: 3417: 3414: 3409: 3405: 3401: 3398: 3395: 3392: 3387: 3383: 3365:(−1,0) − (1,0) 3348: 3345: 3336: 3333: 3320: 3298: 3294: 3271: 3267: 3246: 3224: 3220: 3196: 3174: 3170: 3145: 3125: 3122: 3121: 3120: 3109: 3104: 3096: 3093: 3090: 3087: 3082: 3078: 3074: 3071: 3066: 3062: 3056: 3053: 3050: 3047: 3044: 3041: 3038: 3033: 3030: 3027: 3021: 3016: 3013: 3010: 3007: 2997: 2986: 2983: 2980: 2977: 2974: 2971: 2968: 2965: 2961: 2958: 2955: 2945: 2934: 2931: 2928: 2925: 2922: 2919: 2916: 2913: 2909: 2906: 2903: 2893: 2882: 2879: 2876: 2873: 2870: 2867: 2864: 2861: 2857: 2854: 2851: 2822: 2821: 2808: 2804: 2800: 2797: 2794: 2789: 2785: 2774: 2771: 2768: 2765: 2762: 2759: 2756: 2753: 2750: 2747: 2744: 2741: 2738: 2702: 2698: 2694: 2690: 2686: 2683: 2678: 2674: 2670: 2666: 2662: 2658: 2655: 2650: 2646: 2642: 2637: 2633: 2629: 2625: 2621: 2603: 2602: 2591: 2586: 2580: 2576: 2572: 2569: 2564: 2560: 2556: 2553: 2550: 2545: 2541: 2537: 2534: 2531: 2526: 2522: 2518: 2513: 2509: 2505: 2502: 2499: 2494: 2490: 2486: 2483: 2479: 2475: 2472: 2469: 2466: 2463: 2458: 2454: 2450: 2445: 2441: 2437: 2434: 2431: 2426: 2422: 2418: 2413: 2409: 2405: 2402: 2399: 2396: 2320: 2319: 2304: 2299: 2295: 2291: 2288: 2285: 2280: 2275: 2271: 2267: 2264: 2261: 2255: 2252: 2247: 2243: 2239: 2236: 2233: 2227: 2221: 2216: 2212: 2208: 2205: 2202: 2199: 2194: 2190: 2186: 2183: 2180: 2177: 2174: 2169: 2165: 2161: 2158: 2155: 2149: 2141: 2137: 2133: 2128: 2124: 2106: 2087: 2074: 2065: 2058: 2055: 2054: 2053: 2042: 2037: 2029: 2026: 2021: 2017: 2013: 2010: 2007: 2002: 1998: 1992: 1989: 1986: 1983: 1978: 1975: 1972: 1966: 1961: 1958: 1955: 1952: 1942: 1931: 1925: 1922: 1917: 1913: 1909: 1906: 1903: 1898: 1894: 1888: 1884: 1881: 1878: 1868: 1857: 1854: 1851: 1848: 1845: 1842: 1839: 1836: 1832: 1829: 1826: 1816: 1805: 1802: 1799: 1796: 1793: 1790: 1787: 1784: 1780: 1777: 1774: 1743: 1739: 1734: 1730: 1726: 1723: 1720: 1717: 1712: 1708: 1704: 1701: 1698: 1694: 1690: 1687: 1662: 1658: 1653: 1649: 1645: 1642: 1639: 1636: 1631: 1627: 1623: 1620: 1617: 1613: 1609: 1606: 1582: 1577: 1573: 1569: 1564: 1560: 1556: 1553: 1530: 1525: 1521: 1517: 1512: 1508: 1504: 1501: 1481: 1478: 1475: 1470: 1466: 1462: 1459: 1454: 1450: 1446: 1443: 1438: 1434: 1430: 1427: 1422: 1418: 1394: 1389: 1385: 1381: 1376: 1372: 1368: 1365: 1345: 1342: 1339: 1334: 1330: 1326: 1323: 1318: 1314: 1310: 1307: 1302: 1298: 1294: 1291: 1286: 1282: 1245: 1232: 1200: 1191: 1184: 1181: 1145: 1142: 1111: 1107: 1103: 1098: 1095: 1092: 1089: 1064: 1061: 1056: 1053: 1043:geometric mean 1018: 1015: 1010: 1006: 1000: 999: 988: 983: 979: 975: 972: 969: 966: 963: 958: 954: 950: 947: 944: 941: 938: 935: 929: or  923: 920: 915: 910: 906: 902: 899: 874: 868: 864: 860: 856: 852: 848: 845: 840: 836: 832: 827: 823: 819: 815: 811: 808: 803: 799: 795: 791: 787: 772: 771: 756: 753: 750: 747: 744: 741: 738: 736: 734: 729: 726: 723: 718: 713: 709: 706: 703: 700: 697: 694: 691: 686: 682: 678: 675: 672: 667: 663: 658: 653: 646: 641: 635: 628: 624: 621: 619: 615: 612: 609: 604: 600: 597: 594: 591: 586: 582: 578: 575: 572: 569: 566: 561: 557: 553: 550: 547: 544: 541: 538: 531: 526: 520: 513: 509: 508: 485: 482: 475: 470: 464: 439: 435: 431: 426: 422: 418: 415: 412: 407: 403: 399: 394: 390: 386: 383: 372: 371: 360: 355: 351: 346: 342: 338: 333: 329: 325: 322: 319: 314: 310: 306: 303: 298: 294: 290: 287: 284: 279: 275: 271: 268: 263: 259: 255: 252: 248: 243: 240: 237: 234: 229: 225: 221: 216: 212: 208: 205: 202: 197: 193: 189: 184: 180: 176: 173: 170: 167: 97:in which each 59: 56: 13: 10: 9: 6: 4: 3: 2: 4269: 4258: 4255: 4253: 4250: 4249: 4247: 4234: 4230: 4227: 4222: 4219: 4215: 4210: 4207: 4203: 4198: 4195: 4190: 4184: 4180: 4175: 4174: 4165: 4162: 4157: 4150: 4147: 4142: 4136: 4132: 4127: 4126: 4117: 4115: 4113: 4111: 4109: 4105: 4098: 4096: 4094: 4089: 4086:The study of 4084: 4083: 4075: 4073: 4072: 4067: 4059: 4054: 4037: 4028: 4024: 4020: 4015: 4011: 4007: 4002: 3998: 3994: 3989: 3985: 3981: 3978: 3974: 3966: 3955: 3951: 3947: 3942: 3938: 3934: 3929: 3925: 3921: 3916: 3912: 3908: 3905: 3898: 3894: 3890: 3887: 3878: 3867: 3863: 3859: 3854: 3850: 3846: 3841: 3837: 3833: 3828: 3824: 3820: 3817: 3810: 3806: 3802: 3799: 3792: 3784: 3783: 3782: 3779: 3775: 3770: 3766: 3761: 3742: 3739: 3734: 3730: 3721: 3715: 3709: 3703: 3693: 3689: 3685: 3677: 3654: 3649: 3645: 3641: 3636: 3631: 3627: 3623: 3620: 3615: 3612: 3606: 3602: 3596: 3591: 3587: 3577: 3567: 3562: 3558: 3554: 3549: 3544: 3540: 3536: 3533: 3528: 3525: 3519: 3515: 3509: 3504: 3500: 3492: 3491: 3490: 3487: 3481: 3477: 3469: 3448: 3444: 3437: 3434: 3431: 3426: 3422: 3415: 3407: 3403: 3396: 3393: 3390: 3385: 3381: 3373: 3372: 3371: 3368: 3362: 3358: 3354: 3346: 3344: 3342: 3334: 3332: 3318: 3296: 3292: 3269: 3265: 3244: 3222: 3218: 3210: 3194: 3172: 3168: 3159: 3143: 3130: 3123: 3107: 3102: 3094: 3091: 3088: 3085: 3080: 3076: 3072: 3069: 3064: 3060: 3054: 3051: 3048: 3045: 3042: 3039: 3036: 3031: 3028: 3025: 3019: 3014: 3011: 3008: 3005: 2998: 2981: 2978: 2975: 2972: 2969: 2966: 2959: 2956: 2953: 2946: 2929: 2926: 2923: 2920: 2917: 2914: 2907: 2904: 2901: 2894: 2877: 2874: 2871: 2868: 2865: 2862: 2855: 2852: 2849: 2842: 2841: 2840: 2838: 2833: 2831: 2827: 2806: 2802: 2798: 2795: 2792: 2787: 2783: 2772: 2769: 2766: 2763: 2760: 2757: 2754: 2751: 2748: 2745: 2742: 2739: 2736: 2729: 2728: 2727: 2725: 2721: 2716: 2700: 2692: 2681: 2676: 2668: 2656: 2653: 2648: 2644: 2640: 2635: 2627: 2610: 2608: 2589: 2584: 2578: 2574: 2570: 2567: 2562: 2558: 2554: 2551: 2548: 2543: 2539: 2535: 2532: 2524: 2520: 2516: 2511: 2507: 2500: 2497: 2492: 2488: 2484: 2481: 2477: 2473: 2470: 2467: 2456: 2452: 2448: 2443: 2439: 2432: 2424: 2420: 2416: 2411: 2407: 2397: 2394: 2387: 2386: 2385: 2383: 2379: 2375: 2371: 2367: 2363: 2359: 2355: 2346: 2338: 2334: 2332: 2328: 2323: 2297: 2293: 2286: 2283: 2273: 2269: 2262: 2259: 2253: 2245: 2241: 2234: 2231: 2225: 2214: 2210: 2203: 2200: 2192: 2188: 2181: 2178: 2175: 2167: 2163: 2156: 2153: 2147: 2139: 2135: 2131: 2126: 2122: 2114: 2113: 2112: 2109: 2105: 2101: 2099: 2095: 2090: 2086: 2082: 2077: 2073: 2068: 2064: 2056: 2040: 2035: 2027: 2024: 2019: 2015: 2011: 2008: 2005: 2000: 1996: 1990: 1987: 1984: 1981: 1976: 1973: 1970: 1964: 1959: 1956: 1953: 1950: 1943: 1923: 1920: 1915: 1911: 1907: 1904: 1901: 1896: 1892: 1882: 1879: 1876: 1869: 1852: 1849: 1846: 1843: 1840: 1837: 1830: 1827: 1824: 1817: 1800: 1797: 1794: 1791: 1788: 1785: 1778: 1775: 1772: 1765: 1764: 1763: 1761: 1756: 1741: 1732: 1728: 1721: 1718: 1710: 1706: 1699: 1696: 1692: 1688: 1685: 1677: 1660: 1651: 1647: 1640: 1637: 1629: 1625: 1618: 1615: 1611: 1607: 1604: 1596: 1575: 1571: 1567: 1562: 1558: 1551: 1542: 1523: 1519: 1515: 1510: 1506: 1499: 1479: 1476: 1468: 1464: 1457: 1452: 1448: 1444: 1436: 1432: 1425: 1420: 1416: 1406: 1387: 1383: 1379: 1374: 1370: 1363: 1343: 1340: 1332: 1328: 1321: 1316: 1312: 1308: 1300: 1296: 1289: 1284: 1280: 1270: 1268: 1259: 1255: 1253: 1248: 1244: 1240: 1235: 1231: 1227: 1223: 1219: 1214: 1212: 1208: 1203: 1199: 1194: 1190: 1182: 1180: 1178: 1174: 1171:) point (the 1170: 1165: 1163: 1159: 1155: 1151: 1143: 1141: 1139: 1135: 1131: 1127: 1109: 1105: 1101: 1096: 1093: 1090: 1087: 1080: 1062: 1059: 1054: 1051: 1044: 1040: 1036: 1032: 1028: 1024: 1016: 1014: 1005: 981: 977: 973: 970: 964: 961: 956: 952: 948: 945: 942: 939: 936: 933: 921: 918: 913: 908: 904: 900: 897: 890: 889: 888: 885: 872: 866: 858: 846: 843: 838: 834: 830: 825: 817: 806: 801: 793: 777: 776:metric tensor 751: 745: 742: 739: 737: 727: 724: 721: 716: 711: 704: 698: 695: 692: 689: 684: 680: 676: 673: 670: 665: 661: 656: 651: 644: 622: 620: 613: 610: 607: 602: 592: 589: 584: 580: 576: 573: 567: 559: 555: 551: 548: 539: 536: 529: 499: 498: 497: 483: 480: 473: 437: 433: 429: 424: 420: 416: 413: 410: 405: 401: 397: 392: 388: 384: 381: 358: 353: 344: 340: 336: 331: 327: 320: 317: 312: 308: 304: 301: 296: 292: 288: 285: 282: 277: 273: 269: 266: 261: 257: 253: 250: 246: 241: 238: 227: 223: 219: 214: 210: 203: 195: 191: 187: 182: 178: 168: 165: 158: 157: 156: 154: 149: 147: 143: 139: 135: 131: 127: 123: 119: 114: 112: 108: 104: 100: 96: 93: 89: 73: 69: 64: 57: 55: 53: 49: 45: 41: 37: 32: 29: 27: 23: 19: 4221: 4209: 4197: 4172: 4164: 4155: 4149: 4124: 4092: 4085: 4079: 4069: 3777: 3773: 3768: 3764: 3762: 3687: 3681: 3488: 3479: 3473: 3369: 3360: 3350: 3338: 3135: 2836: 2834: 2829: 2825: 2823: 2723: 2719: 2717: 2611: 2604: 2381: 2377: 2373: 2369: 2365: 2361: 2357: 2353: 2351: 2324: 2321: 2107: 2103: 2102: 2093: 2088: 2084: 2080: 2075: 2071: 2066: 2062: 2060: 1759: 1757: 1678:-axis it is 1675: 1594: 1543: 1407: 1271: 1267:ideal points 1264: 1251: 1246: 1242: 1238: 1233: 1229: 1225: 1221: 1216:Like in the 1215: 1210: 1206: 1201: 1197: 1192: 1188: 1186: 1176: 1166: 1154:right angles 1147: 1125: 1038: 1034: 1030: 1026: 1020: 1003: 1001: 886: 773: 373: 150: 145: 141: 137: 133: 129: 121: 115: 87: 85: 71: 67: 33: 30: 26:real numbers 20:, as in the 15: 1162:hypercycles 146:polar angle 4246:Categories 4188:0387943390 4140:0387906940 4099:References 4066:gyrovector 3209:arc length 1674:. To the 1150:rectangles 1009:and θ 130:polar axis 124:, and the 4021:⁡ 4008:− 3995:⁡ 3982:− 3948:⁡ 3935:− 3922:⁡ 3909:− 3891:⁡ 3860:⁡ 3847:− 3834:⁡ 3821:− 3803:⁡ 3692:hyperbola 3642:− 3624:− 3555:− 3537:− 3438:⁡ 3397:⁡ 3158:horocycle 3092:− 3086:⁡ 3070:⁡ 3049:⁡ 3040:⁡ 3029:⁡ 3006:θ 2979:⁡ 2970:⁡ 2930:θ 2927:⁡ 2918:⁡ 2878:θ 2875:⁡ 2866:⁡ 2770:⁡ 2755:⁡ 2740:⁡ 2654:⁡ 2571:⁡ 2555:⁡ 2549:− 2536:⁡ 2517:− 2501:⁡ 2485:⁡ 2474:⁡ 2462:⟩ 2436:⟨ 2430:⟩ 2404:⟨ 2398:⁡ 2287:⁡ 2263:⁡ 2235:⁡ 2204:⁡ 2182:⁡ 2157:⁡ 2025:⁡ 2006:⁡ 1985:⁡ 1974:⁡ 1951:θ 1921:⁡ 1902:⁡ 1853:θ 1850:⁡ 1841:⁡ 1801:θ 1798:⁡ 1789:⁡ 1722:⁡ 1700:⁡ 1689:⁡ 1641:⁡ 1619:⁡ 1608:⁡ 1597:-axis is 1458:⁡ 1426:⁡ 1322:⁡ 1290:⁡ 1097:⁡ 978:θ 974:− 971:θ 965:⁡ 949:⁡ 937:⁡ 919:π 914:± 905:θ 898:θ 859:θ 844:⁡ 746:⁡ 722:θ 705:θ 699:⁡ 690:⁡ 677:− 671:⁡ 645:θ 608:θ 596:⟩ 593:θ 581:θ 571:⟨ 565:⟩ 556:θ 546:⟨ 540:⁡ 530:θ 474:θ 434:θ 430:− 421:θ 414:θ 341:θ 337:− 328:θ 321:⁡ 305:⁡ 289:⁡ 283:− 270:⁡ 254:⁡ 233:⟩ 224:θ 207:⟨ 201:⟩ 192:θ 175:⟨ 169:⁡ 151:From the 80:(4, 210°) 4229:Archived 3284:, where 1077:and the 1037:> 0, 107:distance 76:(3, 60°) 4131:447–450 3772:,  2376:-axis. 2083:-axis. 1593:to the 1228:-axes. 1130:motions 16:In the 4185:  4179:97–103 4137:  4055:Others 3970:  3964:  3882:  3876:  3725:  3719:  3713:  3707:  3584:  3581:  3419:  3015:arctan 2960:arcosh 2908:arsinh 2856:artanh 2824:where 2471:arcosh 2229:  2223:  2151:  2145:  1960:arctan 1883:artanh 1831:artanh 1779:artanh 1686:artanh 1605:artanh 1173:Origin 1002:where 652:arcosh 242:arcosh 138:radius 4080:From 3187:from 1492:then 1356:then 1169:ideal 1156:(see 144:, or 111:angle 103:plane 101:on a 99:point 90:is a 4183:ISBN 4135:ISBN 4012:tanh 3986:tanh 3939:tanh 3913:tanh 3888:tanh 3851:tanh 3825:tanh 3800:tanh 3435:tanh 3394:tanh 3257:and 3077:cosh 3061:cosh 3046:cosh 3037:sinh 3026:sinh 2976:cosh 2967:cosh 2915:sinh 2863:tanh 2828:and 2793:< 2767:sinh 2752:cosh 2737:tanh 2645:cosh 2568:sinh 2552:sinh 2533:cosh 2498:cosh 2482:cosh 2395:dist 2368:and 2284:cosh 2260:tanh 2232:tanh 2201:cosh 2179:tanh 2154:tanh 2070:and 2016:tanh 1997:tanh 1982:tanh 1971:tanh 1912:tanh 1893:tanh 1838:tanh 1786:tanh 1719:cosh 1697:tanh 1638:cosh 1616:tanh 1477:> 1449:tanh 1417:tanh 1313:tanh 1281:tanh 1224:and 1196:and 1029:= {( 1021:The 946:tanh 934:tanh 835:sinh 743:sinh 681:sinh 662:cosh 537:dist 374:Let 302:sinh 286:sinh 267:cosh 251:cosh 166:dist 122:pole 86:The 50:are 48:tanh 46:and 44:cosh 40:Sinh 4093:not 2924:sin 2872:cos 2100:). 1847:sin 1795:cos 1408:If 1272:If 1126:u,v 1033:): 1031:x,y 962:sec 696:cos 318:cos 136:or 126:ray 4248:: 4181:. 4133:. 4107:^ 3331:. 2715:. 2609:. 2333:. 1755:. 1140:. 1094:ln 778:: 496:: 148:. 54:. 42:, 4191:. 4143:. 4038:) 4029:a 4025:y 4016:2 4003:a 3999:x 3990:2 3979:1 3975:1 3967:, 3956:a 3952:y 3943:2 3930:a 3926:x 3917:2 3906:1 3899:a 3895:y 3879:, 3868:a 3864:y 3855:2 3842:a 3838:x 3829:2 3818:1 3811:a 3807:x 3793:( 3778:a 3774:y 3769:a 3765:x 3748:) 3743:1 3740:+ 3735:2 3731:t 3722:, 3716:0 3710:, 3704:t 3701:( 3688:x 3655:2 3650:b 3646:y 3637:2 3632:b 3628:x 3621:1 3616:+ 3613:1 3607:b 3603:y 3597:= 3592:p 3588:y 3578:, 3568:2 3563:b 3559:y 3550:2 3545:b 3541:x 3534:1 3529:+ 3526:1 3520:b 3516:x 3510:= 3505:p 3501:x 3480:x 3454:) 3449:a 3445:y 3441:( 3432:= 3427:b 3423:y 3416:, 3413:) 3408:a 3404:x 3400:( 3391:= 3386:b 3382:x 3361:x 3319:P 3297:h 3293:P 3270:h 3266:P 3245:O 3223:h 3219:y 3195:P 3173:h 3169:x 3144:P 3108:. 3103:) 3095:1 3089:y 3081:2 3073:x 3065:2 3055:+ 3052:y 3043:x 3032:y 3020:( 3012:2 3009:= 2985:) 2982:y 2973:x 2964:( 2957:= 2954:r 2933:) 2921:r 2912:( 2905:= 2902:y 2881:) 2869:r 2860:( 2853:= 2850:x 2837:x 2830:B 2826:A 2807:2 2803:B 2799:+ 2796:1 2788:2 2784:A 2773:x 2764:B 2761:+ 2758:x 2749:A 2746:= 2743:y 2724:x 2720:x 2701:2 2697:) 2693:y 2689:d 2685:( 2682:+ 2677:2 2673:) 2669:x 2665:d 2661:( 2657:y 2649:2 2641:= 2636:2 2632:) 2628:s 2624:d 2620:( 2590:. 2585:) 2579:2 2575:y 2563:1 2559:y 2544:2 2540:y 2530:) 2525:1 2521:x 2512:2 2508:x 2504:( 2493:1 2489:y 2478:( 2468:= 2465:) 2457:2 2453:y 2449:, 2444:2 2440:x 2433:, 2425:1 2421:y 2417:, 2412:1 2408:x 2401:( 2382:y 2378:x 2374:x 2370:y 2366:x 2362:x 2358:x 2354:x 2318:. 2303:) 2298:l 2294:x 2290:( 2279:) 2274:l 2270:y 2266:( 2254:= 2251:) 2246:a 2242:y 2238:( 2226:, 2220:) 2215:a 2211:x 2207:( 2198:) 2193:a 2189:y 2185:( 2176:= 2173:) 2168:l 2164:y 2160:( 2148:, 2140:a 2136:x 2132:= 2127:l 2123:x 2108:ℓ 2104:y 2094:x 2089:ℓ 2085:x 2081:x 2076:ℓ 2072:y 2067:ℓ 2063:x 2041:. 2036:) 2028:y 2020:2 2012:+ 2009:x 2001:2 1991:+ 1988:x 1977:y 1965:( 1957:2 1954:= 1930:) 1924:y 1916:2 1908:+ 1905:x 1897:2 1887:( 1880:= 1877:r 1856:) 1844:r 1835:( 1828:= 1825:y 1804:) 1792:r 1783:( 1776:= 1773:x 1760:x 1742:) 1738:) 1733:a 1729:y 1725:( 1716:) 1711:a 1707:x 1703:( 1693:( 1676:y 1661:) 1657:) 1652:a 1648:x 1644:( 1635:) 1630:a 1626:y 1622:( 1612:( 1595:x 1581:) 1576:a 1572:y 1568:, 1563:a 1559:x 1555:( 1552:P 1529:) 1524:a 1520:y 1516:, 1511:a 1507:x 1503:( 1500:P 1480:1 1474:) 1469:a 1465:y 1461:( 1453:2 1445:+ 1442:) 1437:a 1433:x 1429:( 1421:2 1393:) 1388:a 1384:y 1380:, 1375:a 1371:x 1367:( 1364:P 1344:1 1341:= 1338:) 1333:a 1329:y 1325:( 1317:2 1309:+ 1306:) 1301:a 1297:x 1293:( 1285:2 1252:y 1247:a 1243:y 1239:x 1234:a 1230:x 1226:y 1222:x 1211:x 1207:y 1202:a 1198:y 1193:a 1189:x 1177:x 1110:y 1106:/ 1102:x 1091:= 1088:u 1063:y 1060:x 1055:= 1052:v 1039:y 1035:x 1027:Q 1011:0 1007:0 1004:r 987:) 982:0 968:( 957:0 953:r 943:= 940:r 922:2 909:0 901:= 873:. 867:2 863:) 855:d 851:( 847:r 839:2 831:+ 826:2 822:) 818:r 814:d 810:( 807:= 802:2 798:) 794:s 790:d 786:( 755:) 752:r 749:( 740:= 728:0 725:= 717:| 712:) 708:) 702:( 693:r 685:2 674:r 666:2 657:( 640:d 634:d 623:= 614:0 611:= 603:| 599:) 590:+ 585:1 577:, 574:r 568:, 560:1 552:, 549:r 543:( 525:d 519:d 484:0 481:= 469:d 463:d 438:1 425:2 417:= 411:, 406:2 402:r 398:= 393:1 389:r 385:= 382:r 359:. 354:) 350:) 345:1 332:2 324:( 313:2 309:r 297:1 293:r 278:2 274:r 262:1 258:r 247:( 239:= 236:) 228:2 220:, 215:2 211:r 204:, 196:1 188:, 183:1 179:r 172:( 82:. 72:L 68:O

Index

hyperbolic plane
Euclidean plane
real numbers
Gaussian curvature
Sinh
cosh
tanh
hyperbolic functions

two-dimensional
coordinate system
point
plane
distance
angle
Cartesian system
ray
hyperbolic law of cosines
metric tensor
Poincaré half-plane model
geometric mean
hyperbolic angle
motions
hyperbolic rotations
hyperbolic coordinates
rectangles
right angles
Lambert quadrilateral
hypercycles
ideal

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