Knowledge (XXG)

Identity (mathematics)

Source 📝

46: 1245: 2820:
states that one can convert any trigonometric identity into a hyperbolic identity by expanding it completely in terms of integer powers of sines and cosines, changing sine to sinh and cosine to cosh, and switching the sign of every term which contains a product of an
2710: 2052: 3184: 2404: 1810: 1912: 1073: 2537: 2320: 2240: 3293: 1009: 1670: 810: 1078: 439: 241: 133: 2913: 2796: 2133: 1447:
The logarithm of a product is the sum of the logarithms of the numbers being multiplied; the logarithm of the ratio of two numbers is the difference of the logarithms. The logarithm of the
3031: 1411: 632: 381: 1349: 1285:, but 2 to the 4 is 8 (or 4,096) whereas 2 to the 3 is 2 (or 2,417,851,639,229,258,349,412,352). When no parentheses are written, by convention the order is top-down, not bottom-up: 705: 2982: 1559: 1510: 2563: 869: 1918: 183: 921: 1047: 947: 551: 892: 834: 71: 510: 3047: 2326: 1677: 1821: 1463:. The following table lists these identities with examples. Each of the identities can be derived after substitution of the logarithm definitions 1240:{\displaystyle {\begin{aligned}b^{m+n}&=b^{m}\cdot b^{n}\\(b^{m})^{n}&=b^{m\cdot n}\\(b\cdot c)^{n}&=b^{n}\cdot c^{n}\end{aligned}}} 740:
These identities are useful whenever expressions involving trigonometric functions need to be simplified. Another important application is the
3750: 3729: 3710: 3540: 3389:
Pratt, Vaughan, "Algebra", The Stanford Encyclopedia of Philosophy (Winter 2022 Edition), Edward N. Zalta & Uri Nodelman (eds.), URL:
2445: 3805: 2251: 3677: 3606: 2140: 3800: 716: 3195: 3316: 952:
Another group of trigonometric identities concerns the so-called addition/subtraction formulas (e.g. the double-angle identity
955: 1583: 3767: 754: 3298:
So, these formulas are identities in every monoid. As for any equality, the formulas without quantifier are often called
386: 188: 3776: 76: 3795: 2854: 2739: 2064: 745: 2987: 2548: 1354: 560: 309: 2832:
gives a direct relationship between the trigonometric functions and the hyperbolic ones that does not involve
1291: 3527:
Schaum's outline of theory and problems of elements of statistics. I, Descriptive statistics and probability
637: 260: 2938: 2813: 1422: 722: 458: 303: 279: 256: 3378: 2705:{\displaystyle \log _{b}(x)={\frac {\log _{10}(x)}{\log _{10}(b)}}={\frac {\log _{e}(x)}{\log _{e}(b)}}.} 3630: 2829: 2544: 1515: 1466: 2047:{\displaystyle \log _{2}(16)=\log _{2}\!\left({\frac {64}{4}}\right)=\log _{2}(64)-\log _{2}(4)=6-2=4} 1049:), which can be used to break down expressions of larger angles into those with smaller constituents. 2845: 2822: 50: 842: 3311: 2848: 2807: 283: 142: 3657: 3577: 897: 45: 3614: 1014: 926: 3746: 3725: 3706: 3673: 3626: 3602: 3536: 3321: 515: 306:, and an identity is an equality between functions that are differently defined. For example, 35: 877: 819: 56: 3740: 3569: 3033:
is often left implicit, when it is stated that the formula is an identity. For example, the
31: 3302:. In other words, an identity is an equation that is true for all values of the variables. 483: 3780: 3653: 3634: 3179:{\displaystyle \forall x,y,z:x*(y*z)=(x*y)*z,\quad \forall x:x*1=x,\quad \forall x:1*x=x,} 2399:{\displaystyle \log _{10}\!{\sqrt {1000}}={\frac {1}{2}}\log _{10}1000={\frac {3}{2}}=1.5} 39: 2833: 1058: 17: 3789: 3525: 3474: 2932: 2812:
The hyperbolic functions satisfy many identities, all of them similar in form to the
751:
One of the most prominent examples of trigonometric identities involves the equation
475: 3641:. Handbook of Theoretical Computer Science. Vol. B. Elsevier. pp. 243–320. 3450: 1805:{\displaystyle \log _{3}(243)=\log _{3}(9\cdot 27)=\log _{3}(9)+\log _{3}(27)=2+3=5} 3661: 3390: 2928: 730: 744:
of non-trigonometric functions: a common technique which involves first using the
3700: 3596: 3532: 3499: 2557:
can be determined using either of these two logarithms by the previous formula:
1907:{\displaystyle \log _{b}\!\left({\frac {x}{y}}\right)=\log _{b}(x)-\log _{b}(y)} 1274: 1251: 813: 454: 248: 136: 3773: 442: 748:, and then simplifying the resulting integral with a trigonometric identity. 3672:
Monographs on Theoretical Computer Science. Vol. 25. Berlin: Springer.
3426: 1436: 3402: 282:) produce the same value for all values of the variables within a certain 3299: 741: 734: 707:, can be useful in simplifying algebraic expressions and expanding them. 3581: 1064: 554: 3379:
http://encyclopediaofmath.org/index.php?title=Equation&oldid=32613
3038: 3573: 3557: 733:, which are identities involving both angles and side lengths of a 3669: 3034: 2532:{\displaystyle \log _{b}(x)={\frac {\log _{k}(x)}{\log _{k}(b)}}.} 726: 44: 2315:{\displaystyle \log _{b}\!{\sqrt{x}}={\frac {\log _{b}(x)}{p}}} 1273:
Also unlike addition and multiplication, exponentiation is not
2235:{\displaystyle \log _{2}(64)=\log _{2}(2^{6})=6\log _{2}(2)=6} 1455:
times the logarithm of the number itself; the logarithm of a
3288:{\displaystyle x*(y*z)=(x*y)*z,\qquad x*1=x,\qquad 1*x=x.} 1250:
Unlike addition and multiplication, exponentiation is not
725:
are identities involving certain functions of one or more
441:
are identities. Identities are sometimes indicated by the
27:
Equation that is satisfied for all values of the variables
3770:
Online encyclopedia of mathematical identities (archived)
1004:{\displaystyle \sin(2\theta )=2\sin \theta \cos \theta } 3427:"Identity – math word definition – Math Open Reference" 1665:{\displaystyle \log _{b}(xy)=\log _{b}(x)+\log _{b}(y)} 3198: 3050: 2990: 2941: 2857: 2742: 2566: 2448: 2329: 2254: 2143: 2067: 1921: 1824: 1680: 1586: 1518: 1469: 1357: 1294: 1076: 1017: 958: 929: 900: 880: 845: 822: 757: 640: 563: 518: 486: 389: 312: 191: 145: 79: 59: 805:{\displaystyle \sin ^{2}\theta +\cos ^{2}\theta =1,} 894:, not all. For example, this equation is true when 434:{\displaystyle \cos ^{2}\theta +\sin ^{2}\theta =1} 236:{\displaystyle \cos ^{2}\theta +\sin ^{2}\theta =1} 3524: 3287: 3178: 3025: 2976: 2907: 2790: 2704: 2531: 2398: 2314: 2234: 2127: 2046: 1906: 1804: 1664: 1553: 1504: 1459:th root is the logarithm of the number divided by 1405: 1343: 1239: 1041: 1003: 941: 915: 886: 863: 828: 804: 699: 626: 545: 504: 433: 375: 235: 177: 127: 65: 2340: 2265: 1957: 1835: 128:{\displaystyle (x,y)=(\cos \theta ,\sin \theta )} 3601:(3rd ed.). Cengage Learning. p. 1155. 3391:https://plato.stanford.edu/entries/algebra/#Laws 2908:{\displaystyle \forall x_{1},\ldots ,x_{n}:s=t,} 3345:All statements in this section can be found in 1067:exponents, provided that the base is non-zero: 746:substitution rule with a trigonometric function 737:. Only the former are covered in this article. 2791:{\displaystyle b=x^{\frac {1}{\log _{b}(x)}}.} 2128:{\displaystyle \log _{b}(x^{p})=p\log _{b}(x)} 266: to another mathematical expression  1427:Several important formulas, sometimes called 8: 3523:Bernstein, Stephen; Bernstein, Ruth (1999), 3377:Equation. Encyclopedia of Mathematics. URL: 3354: 3026:{\displaystyle \forall x_{1},\ldots ,x_{n}} 476:Factorization § Recognizable patterns 3666:Universal Algebra for Computer Scientists 3197: 3049: 3017: 2998: 2989: 2965: 2946: 2940: 2884: 2865: 2856: 2763: 2753: 2741: 2678: 2654: 2647: 2623: 2599: 2592: 2571: 2565: 2547:calculate the logarithms to bases 10 and 2505: 2481: 2474: 2453: 2447: 2426:) can be computed from the logarithms of 2380: 2365: 2351: 2341: 2334: 2328: 2288: 2281: 2271: 2266: 2259: 2253: 2208: 2189: 2173: 2148: 2142: 2107: 2088: 2072: 2066: 2008: 1983: 1962: 1951: 1926: 1920: 1886: 1861: 1840: 1829: 1823: 1766: 1741: 1710: 1685: 1679: 1644: 1619: 1591: 1585: 1534: 1529: 1517: 1485: 1480: 1468: 1406:{\displaystyle (b^{p})^{q}=b^{p\cdot q}.} 1388: 1375: 1365: 1356: 1327: 1319: 1304: 1299: 1293: 1227: 1214: 1197: 1165: 1148: 1138: 1121: 1108: 1085: 1077: 1075: 1016: 957: 928: 899: 879: 844: 821: 781: 762: 756: 658: 645: 639: 627:{\displaystyle (a+b)^{2}=a^{2}+2ab+b^{2}} 618: 593: 580: 562: 517: 485: 413: 394: 388: 376:{\displaystyle (a+b)^{2}=a^{2}+2ab+b^{2}} 367: 342: 329: 311: 215: 196: 190: 163: 150: 144: 78: 58: 1563: 3558:"109. Mnemonic for Hyperbolic Formulae" 3370: 3350: 3346: 3338: 1344:{\displaystyle b^{p^{q}}:=b^{(p^{q})},} 2553:. Logarithms with respect to any base 1063:The following identities hold for all 700:{\displaystyle a^{2}-b^{2}=(a+b)(a-b)} 3531:, Schaum's outline series, New York: 7: 3774:A Collection of Algebraic Identities 2977:{\displaystyle x_{1},\ldots ,x_{n}.} 3598:Technical mathematics with calculus 874:is only true for certain values of 3720:Kate, S.K.; Bhapkar, H.R. (2009). 3149: 3121: 3051: 2991: 2858: 2434:with respect to an arbitrary base 836:. On the other hand, the equation 557:, while other identities, such as 25: 3684:Here: Def.1 of Sect.3.2.1, p.160. 1554:{\displaystyle y=b^{\log _{b}y},} 1505:{\displaystyle x=b^{\log _{b}x},} 1443:Product, quotient, power and root 3041:are often given as the formulas 2844:Formally, an identity is a true 717:List of trigonometric identities 3595:Peterson, John Charles (2003). 3317:List of mathematical identities 3266: 3247: 3148: 3120: 139:, which satisfies the equation 3705:. Barrons Educational Series. 3633:(1990). "Rewrite Systems". In 3235: 3223: 3217: 3205: 3108: 3096: 3090: 3078: 2802:Hyperbolic function identities 2778: 2772: 2693: 2687: 2669: 2663: 2638: 2632: 2614: 2608: 2586: 2580: 2520: 2514: 2496: 2490: 2468: 2462: 2303: 2297: 2223: 2217: 2195: 2182: 2163: 2157: 2122: 2116: 2094: 2081: 2023: 2017: 1998: 1992: 1941: 1935: 1901: 1895: 1876: 1870: 1781: 1775: 1756: 1750: 1731: 1719: 1700: 1694: 1659: 1653: 1634: 1628: 1609: 1600: 1372: 1358: 1333: 1320: 1283:(2 · 3) · 4 = 2 · (3 · 4) = 24 1194: 1181: 1145: 1131: 1036: 1024: 974: 965: 864:{\displaystyle \cos \theta =1} 694: 682: 679: 667: 577: 564: 534: 525: 326: 313: 122: 98: 92: 80: 1: 3742:Adventures in Problem Solving 3556:Osborn, G. (1 January 1902). 2438:using the following formula: 1279:(2 + 3) + 4 = 2 + (3 + 4) = 9 457:. Formally, an identity is a 178:{\displaystyle x^{2}+y^{2}=1} 3768:The Encyclopedia of Equation 2825:number of hyperbolic sines. 480:Certain identities, such as 3639:Formal Models and Semantics 3357:, p. 1-1, for example. 2840:Logic and universal algebra 1011:, the addition formula for 3822: 3724:. Technical Publications. 3652:Wolfgang Wechsler (1992). 3500:"Trigonometric Identities" 2805: 1420: 1056: 916:{\displaystyle \theta =0,} 714: 473: 278:(which might contain some 29: 3806:Equivalence (mathematics) 3699:Downing, Douglas (2003). 1042:{\displaystyle \tan(x+y)} 942:{\displaystyle \theta =2} 729:. They are distinct from 3562:The Mathematical Gazette 2814:trigonometric identities 2733:, the base is given by: 1561:in the left hand sides. 1451:th power of a number is 723:trigonometric identities 711:Trigonometric identities 546:{\displaystyle a+(-a)=0} 30:Not to be confused with 3801:Mathematical identities 3355:Kate & Bhapkar 2009 887:{\displaystyle \theta } 829:{\displaystyle \theta } 261:mathematical expression 66:{\displaystyle \theta } 18:Mathematical identities 3745:. Universities Press. 3475:"Algebraic Identities" 3289: 3180: 3027: 2984:The quantifier prefix 2978: 2909: 2846:universally quantified 2792: 2706: 2545:scientific calculators 2533: 2400: 2316: 2236: 2129: 2048: 1908: 1806: 1666: 1555: 1506: 1429:logarithmic identities 1423:Logarithmic identities 1417:Logarithmic identities 1407: 1351:  whereas   1345: 1241: 1053:Exponential identities 1043: 1005: 943: 917: 888: 865: 830: 812:which is true for all 806: 701: 628: 547: 506: 459:universally quantified 435: 377: 244: 237: 179: 129: 67: 3722:Basics Of Mathematics 3631:Jean-Pierre Jouannaud 3615:Chapter 26, page 1155 3403:"Mathwords: Identity" 3290: 3181: 3028: 2979: 2910: 2830:Gudermannian function 2793: 2729:) to an unknown base 2719:and its logarithm log 2707: 2534: 2401: 2317: 2237: 2130: 2049: 1909: 1807: 1667: 1556: 1507: 1408: 1346: 1277:either. For example, 1242: 1044: 1006: 944: 918: 889: 866: 831: 807: 702: 629: 548: 507: 505:{\displaystyle a+0=a} 436: 378: 238: 180: 130: 68: 48: 3739:Shirali, S. (2002). 3702:Algebra the Easy Way 3196: 3048: 2988: 2939: 2855: 2740: 2564: 2446: 2327: 2252: 2141: 2065: 1919: 1822: 1678: 1584: 1516: 1467: 1355: 1292: 1074: 1015: 956: 927: 898: 878: 843: 820: 755: 638: 561: 553:, form the basis of 516: 484: 470:Algebraic identities 387: 310: 189: 143: 77: 57: 51:Pythagorean identity 49:Visual proof of the 3498:Stapel, Elizabeth. 3431:www.mathopenref.com 3312:Accounting identity 2808:Hyperbolic function 731:triangle identities 284:domain of discourse 3796:Elementary algebra 3779:2011-10-01 at the 3658:Grzegorz Rozenberg 3451:"Basic Identities" 3353:, p. 275, or 3285: 3176: 3023: 2974: 2905: 2788: 2702: 2529: 2396: 2312: 2232: 2125: 2044: 1904: 1802: 1662: 1551: 1502: 1403: 1341: 1237: 1235: 1039: 1001: 939: 913: 884: 861: 826: 802: 697: 624: 543: 502: 431: 373: 294:is an identity if 286:. In other words, 245: 233: 175: 125: 63: 3752:978-81-7371-413-9 3731:978-81-8431-755-8 3712:978-0-7641-1972-9 3627:Nachum Dershowitz 3542:978-0-07-005023-5 3407:www.mathwords.com 3322:Law (mathematics) 2782: 2697: 2642: 2524: 2416:The logarithm log 2409: 2408: 2388: 2359: 2346: 2310: 2276: 1970: 1848: 1260:2 · 3 = 3 · 2 = 6 1256:2 + 3 = 3 + 2 = 5 465:Common identities 36:identity function 16:(Redirected from 3813: 3756: 3735: 3716: 3685: 3683: 3649: 3643: 3642: 3623: 3617: 3612: 3592: 3586: 3585: 3553: 3547: 3545: 3530: 3520: 3514: 3513: 3511: 3510: 3495: 3489: 3488: 3486: 3485: 3471: 3465: 3464: 3462: 3461: 3447: 3441: 3440: 3438: 3437: 3423: 3417: 3416: 3414: 3413: 3399: 3393: 3387: 3381: 3375: 3358: 3343: 3294: 3292: 3291: 3286: 3185: 3183: 3182: 3177: 3032: 3030: 3029: 3024: 3022: 3021: 3003: 3002: 2983: 2981: 2980: 2975: 2970: 2969: 2951: 2950: 2926: 2920: 2914: 2912: 2911: 2906: 2889: 2888: 2870: 2869: 2797: 2795: 2794: 2789: 2784: 2783: 2781: 2768: 2767: 2754: 2711: 2709: 2708: 2703: 2698: 2696: 2683: 2682: 2672: 2659: 2658: 2648: 2643: 2641: 2628: 2627: 2617: 2604: 2603: 2593: 2576: 2575: 2539: 2538: 2536: 2535: 2530: 2525: 2523: 2510: 2509: 2499: 2486: 2485: 2475: 2458: 2457: 2405: 2403: 2402: 2397: 2389: 2381: 2370: 2369: 2360: 2352: 2347: 2342: 2339: 2338: 2321: 2319: 2318: 2313: 2311: 2306: 2293: 2292: 2282: 2277: 2275: 2267: 2264: 2263: 2241: 2239: 2238: 2233: 2213: 2212: 2194: 2193: 2178: 2177: 2153: 2152: 2135: 2134: 2132: 2131: 2126: 2112: 2111: 2093: 2092: 2077: 2076: 2053: 2051: 2050: 2045: 2013: 2012: 1988: 1987: 1975: 1971: 1963: 1956: 1955: 1931: 1930: 1913: 1911: 1910: 1905: 1891: 1890: 1866: 1865: 1853: 1849: 1841: 1834: 1833: 1811: 1809: 1808: 1803: 1771: 1770: 1746: 1745: 1715: 1714: 1690: 1689: 1672: 1671: 1669: 1668: 1663: 1649: 1648: 1624: 1623: 1596: 1595: 1564: 1560: 1558: 1557: 1552: 1547: 1546: 1539: 1538: 1511: 1509: 1508: 1503: 1498: 1497: 1490: 1489: 1462: 1458: 1454: 1450: 1439:to one another: 1412: 1410: 1409: 1404: 1399: 1398: 1380: 1379: 1370: 1369: 1350: 1348: 1347: 1342: 1337: 1336: 1332: 1331: 1311: 1310: 1309: 1308: 1284: 1280: 1269: 1265: 1261: 1257: 1246: 1244: 1243: 1238: 1236: 1232: 1231: 1219: 1218: 1202: 1201: 1176: 1175: 1153: 1152: 1143: 1142: 1126: 1125: 1113: 1112: 1096: 1095: 1048: 1046: 1045: 1040: 1010: 1008: 1007: 1002: 948: 946: 945: 940: 922: 920: 919: 914: 893: 891: 890: 885: 870: 868: 867: 862: 835: 833: 832: 827: 811: 809: 808: 803: 786: 785: 767: 766: 706: 704: 703: 698: 663: 662: 650: 649: 633: 631: 630: 625: 623: 622: 598: 597: 585: 584: 552: 550: 549: 544: 511: 509: 508: 503: 452: 448: 440: 438: 437: 432: 418: 417: 399: 398: 382: 380: 379: 374: 372: 371: 347: 346: 334: 333: 302:define the same 242: 240: 239: 234: 220: 219: 201: 200: 184: 182: 181: 176: 168: 167: 155: 154: 134: 132: 131: 126: 72: 70: 69: 64: 53:: for any angle 32:identity element 21: 3821: 3820: 3816: 3815: 3814: 3812: 3811: 3810: 3786: 3785: 3781:Wayback Machine 3764: 3759: 3753: 3738: 3732: 3719: 3713: 3698: 3694: 3689: 3688: 3680: 3654:Wilfried Brauer 3651: 3650: 3646: 3635:Jan van Leeuwen 3625: 3624: 3620: 3609: 3594: 3593: 3589: 3574:10.2307/3602492 3555: 3554: 3550: 3543: 3522: 3521: 3517: 3508: 3506: 3497: 3496: 3492: 3483: 3481: 3479:www.sosmath.com 3473: 3472: 3468: 3459: 3457: 3449: 3448: 3444: 3435: 3433: 3425: 3424: 3420: 3411: 3409: 3401: 3400: 3396: 3388: 3384: 3376: 3372: 3367: 3362: 3361: 3344: 3340: 3335: 3330: 3308: 3194: 3193: 3046: 3045: 3013: 2994: 2986: 2985: 2961: 2942: 2937: 2936: 2922: 2916: 2880: 2861: 2853: 2852: 2842: 2834:complex numbers 2810: 2804: 2759: 2758: 2749: 2738: 2737: 2724: 2715:Given a number 2674: 2673: 2650: 2649: 2619: 2618: 2595: 2594: 2567: 2562: 2561: 2501: 2500: 2477: 2476: 2449: 2444: 2443: 2442: 2421: 2414: 2361: 2330: 2325: 2324: 2284: 2283: 2255: 2250: 2249: 2204: 2185: 2169: 2144: 2139: 2138: 2103: 2084: 2068: 2063: 2062: 2061: 2004: 1979: 1958: 1947: 1922: 1917: 1916: 1882: 1857: 1836: 1825: 1820: 1819: 1762: 1737: 1706: 1681: 1676: 1675: 1640: 1615: 1587: 1582: 1581: 1580: 1530: 1525: 1514: 1513: 1481: 1476: 1465: 1464: 1460: 1456: 1452: 1448: 1445: 1425: 1419: 1384: 1371: 1361: 1353: 1352: 1323: 1315: 1300: 1295: 1290: 1289: 1282: 1278: 1267: 1263: 1259: 1255: 1254:. For example, 1234: 1233: 1223: 1210: 1203: 1193: 1178: 1177: 1161: 1154: 1144: 1134: 1128: 1127: 1117: 1104: 1097: 1081: 1072: 1071: 1061: 1055: 1013: 1012: 954: 953: 925: 924: 923:but false when 896: 895: 876: 875: 841: 840: 818: 817: 777: 758: 753: 752: 721:Geometrically, 719: 713: 654: 641: 636: 635: 614: 589: 576: 559: 558: 514: 513: 482: 481: 478: 472: 467: 450: 446: 409: 390: 385: 384: 363: 338: 325: 308: 307: 211: 192: 187: 186: 159: 146: 141: 140: 75: 74: 55: 54: 43: 40:identity matrix 28: 23: 22: 15: 12: 11: 5: 3819: 3817: 3809: 3808: 3803: 3798: 3788: 3787: 3784: 3783: 3771: 3763: 3762:External links 3760: 3758: 3757: 3751: 3736: 3730: 3717: 3711: 3695: 3693: 3690: 3687: 3686: 3678: 3644: 3618: 3607: 3587: 3548: 3541: 3515: 3490: 3466: 3442: 3418: 3394: 3382: 3369: 3368: 3366: 3363: 3360: 3359: 3337: 3336: 3334: 3331: 3329: 3326: 3325: 3324: 3319: 3314: 3307: 3304: 3296: 3295: 3284: 3281: 3278: 3275: 3272: 3269: 3265: 3262: 3259: 3256: 3253: 3250: 3246: 3243: 3240: 3237: 3234: 3231: 3228: 3225: 3222: 3219: 3216: 3213: 3210: 3207: 3204: 3201: 3187: 3186: 3175: 3172: 3169: 3166: 3163: 3160: 3157: 3154: 3151: 3147: 3144: 3141: 3138: 3135: 3132: 3129: 3126: 3123: 3119: 3116: 3113: 3110: 3107: 3104: 3101: 3098: 3095: 3092: 3089: 3086: 3083: 3080: 3077: 3074: 3071: 3068: 3065: 3062: 3059: 3056: 3053: 3020: 3016: 3012: 3009: 3006: 3001: 2997: 2993: 2973: 2968: 2964: 2960: 2957: 2954: 2949: 2945: 2933:free variables 2931:with no other 2904: 2901: 2898: 2895: 2892: 2887: 2883: 2879: 2876: 2873: 2868: 2864: 2860: 2841: 2838: 2806:Main article: 2803: 2800: 2799: 2798: 2787: 2780: 2777: 2774: 2771: 2766: 2762: 2757: 2752: 2748: 2745: 2720: 2713: 2712: 2701: 2695: 2692: 2689: 2686: 2681: 2677: 2671: 2668: 2665: 2662: 2657: 2653: 2646: 2640: 2637: 2634: 2631: 2626: 2622: 2616: 2613: 2610: 2607: 2602: 2598: 2591: 2588: 2585: 2582: 2579: 2574: 2570: 2541: 2540: 2528: 2522: 2519: 2516: 2513: 2508: 2504: 2498: 2495: 2492: 2489: 2484: 2480: 2473: 2470: 2467: 2464: 2461: 2456: 2452: 2417: 2413: 2412:Change of base 2410: 2407: 2406: 2395: 2392: 2387: 2384: 2379: 2376: 2373: 2368: 2364: 2358: 2355: 2350: 2345: 2337: 2333: 2322: 2309: 2305: 2302: 2299: 2296: 2291: 2287: 2280: 2274: 2270: 2262: 2258: 2247: 2243: 2242: 2231: 2228: 2225: 2222: 2219: 2216: 2211: 2207: 2203: 2200: 2197: 2192: 2188: 2184: 2181: 2176: 2172: 2168: 2165: 2162: 2159: 2156: 2151: 2147: 2136: 2124: 2121: 2118: 2115: 2110: 2106: 2102: 2099: 2096: 2091: 2087: 2083: 2080: 2075: 2071: 2059: 2055: 2054: 2043: 2040: 2037: 2034: 2031: 2028: 2025: 2022: 2019: 2016: 2011: 2007: 2003: 2000: 1997: 1994: 1991: 1986: 1982: 1978: 1974: 1969: 1966: 1961: 1954: 1950: 1946: 1943: 1940: 1937: 1934: 1929: 1925: 1914: 1903: 1900: 1897: 1894: 1889: 1885: 1881: 1878: 1875: 1872: 1869: 1864: 1860: 1856: 1852: 1847: 1844: 1839: 1832: 1828: 1817: 1813: 1812: 1801: 1798: 1795: 1792: 1789: 1786: 1783: 1780: 1777: 1774: 1769: 1765: 1761: 1758: 1755: 1752: 1749: 1744: 1740: 1736: 1733: 1730: 1727: 1724: 1721: 1718: 1713: 1709: 1705: 1702: 1699: 1696: 1693: 1688: 1684: 1673: 1661: 1658: 1655: 1652: 1647: 1643: 1639: 1636: 1633: 1630: 1627: 1622: 1618: 1614: 1611: 1608: 1605: 1602: 1599: 1594: 1590: 1578: 1574: 1573: 1570: 1567: 1550: 1545: 1542: 1537: 1533: 1528: 1524: 1521: 1501: 1496: 1493: 1488: 1484: 1479: 1475: 1472: 1444: 1441: 1421:Main article: 1418: 1415: 1414: 1413: 1402: 1397: 1394: 1391: 1387: 1383: 1378: 1374: 1368: 1364: 1360: 1340: 1335: 1330: 1326: 1322: 1318: 1314: 1307: 1303: 1298: 1248: 1247: 1230: 1226: 1222: 1217: 1213: 1209: 1206: 1204: 1200: 1196: 1192: 1189: 1186: 1183: 1180: 1179: 1174: 1171: 1168: 1164: 1160: 1157: 1155: 1151: 1147: 1141: 1137: 1133: 1130: 1129: 1124: 1120: 1116: 1111: 1107: 1103: 1100: 1098: 1094: 1091: 1088: 1084: 1080: 1079: 1059:Exponentiation 1057:Main article: 1054: 1051: 1038: 1035: 1032: 1029: 1026: 1023: 1020: 1000: 997: 994: 991: 988: 985: 982: 979: 976: 973: 970: 967: 964: 961: 938: 935: 932: 912: 909: 906: 903: 883: 872: 871: 860: 857: 854: 851: 848: 825: 801: 798: 795: 792: 789: 784: 780: 776: 773: 770: 765: 761: 715:Main article: 712: 709: 696: 693: 690: 687: 684: 681: 678: 675: 672: 669: 666: 661: 657: 653: 648: 644: 621: 617: 613: 610: 607: 604: 601: 596: 592: 588: 583: 579: 575: 572: 569: 566: 542: 539: 536: 533: 530: 527: 524: 521: 501: 498: 495: 492: 489: 471: 468: 466: 463: 430: 427: 424: 421: 416: 412: 408: 405: 402: 397: 393: 370: 366: 362: 359: 356: 353: 350: 345: 341: 337: 332: 328: 324: 321: 318: 315: 232: 229: 226: 223: 218: 214: 210: 207: 204: 199: 195: 174: 171: 166: 162: 158: 153: 149: 124: 121: 118: 115: 112: 109: 106: 103: 100: 97: 94: 91: 88: 85: 82: 62: 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 3818: 3807: 3804: 3802: 3799: 3797: 3794: 3793: 3791: 3782: 3778: 3775: 3772: 3769: 3766: 3765: 3761: 3754: 3748: 3744: 3743: 3737: 3733: 3727: 3723: 3718: 3714: 3708: 3704: 3703: 3697: 3696: 3691: 3681: 3679:3-540-54280-9 3675: 3671: 3667: 3663: 3659: 3655: 3648: 3645: 3640: 3636: 3632: 3628: 3622: 3619: 3616: 3610: 3608:0-7668-6189-9 3604: 3600: 3599: 3591: 3588: 3583: 3579: 3575: 3571: 3567: 3563: 3559: 3552: 3549: 3544: 3538: 3534: 3529: 3528: 3519: 3516: 3505: 3501: 3494: 3491: 3480: 3476: 3470: 3467: 3456: 3452: 3446: 3443: 3432: 3428: 3422: 3419: 3408: 3404: 3398: 3395: 3392: 3386: 3383: 3380: 3374: 3371: 3364: 3356: 3352: 3349:, Section 4, 3348: 3342: 3339: 3332: 3327: 3323: 3320: 3318: 3315: 3313: 3310: 3309: 3305: 3303: 3301: 3282: 3279: 3276: 3273: 3270: 3267: 3263: 3260: 3257: 3254: 3251: 3248: 3244: 3241: 3238: 3232: 3229: 3226: 3220: 3214: 3211: 3208: 3202: 3199: 3192: 3191: 3190: 3189:or, shortly, 3173: 3170: 3167: 3164: 3161: 3158: 3155: 3152: 3145: 3142: 3139: 3136: 3133: 3130: 3127: 3124: 3117: 3114: 3111: 3105: 3102: 3099: 3093: 3087: 3084: 3081: 3075: 3072: 3069: 3066: 3063: 3060: 3057: 3054: 3044: 3043: 3042: 3040: 3036: 3018: 3014: 3010: 3007: 3004: 2999: 2995: 2971: 2966: 2962: 2958: 2955: 2952: 2947: 2943: 2934: 2930: 2925: 2919: 2902: 2899: 2896: 2893: 2890: 2885: 2881: 2877: 2874: 2871: 2866: 2862: 2850: 2847: 2839: 2837: 2835: 2831: 2826: 2824: 2819: 2818:Osborn's rule 2815: 2809: 2801: 2785: 2775: 2769: 2764: 2760: 2755: 2750: 2746: 2743: 2736: 2735: 2734: 2732: 2728: 2723: 2718: 2699: 2690: 2684: 2679: 2675: 2666: 2660: 2655: 2651: 2644: 2635: 2629: 2624: 2620: 2611: 2605: 2600: 2596: 2589: 2583: 2577: 2572: 2568: 2560: 2559: 2558: 2556: 2552: 2551: 2546: 2526: 2517: 2511: 2506: 2502: 2493: 2487: 2482: 2478: 2471: 2465: 2459: 2454: 2450: 2441: 2440: 2439: 2437: 2433: 2429: 2425: 2420: 2411: 2393: 2390: 2385: 2382: 2377: 2374: 2371: 2366: 2362: 2356: 2353: 2348: 2343: 2335: 2331: 2323: 2307: 2300: 2294: 2289: 2285: 2278: 2272: 2268: 2260: 2256: 2248: 2245: 2244: 2229: 2226: 2220: 2214: 2209: 2205: 2201: 2198: 2190: 2186: 2179: 2174: 2170: 2166: 2160: 2154: 2149: 2145: 2137: 2119: 2113: 2108: 2104: 2100: 2097: 2089: 2085: 2078: 2073: 2069: 2060: 2057: 2056: 2041: 2038: 2035: 2032: 2029: 2026: 2020: 2014: 2009: 2005: 2001: 1995: 1989: 1984: 1980: 1976: 1972: 1967: 1964: 1959: 1952: 1948: 1944: 1938: 1932: 1927: 1923: 1915: 1898: 1892: 1887: 1883: 1879: 1873: 1867: 1862: 1858: 1854: 1850: 1845: 1842: 1837: 1830: 1826: 1818: 1815: 1814: 1799: 1796: 1793: 1790: 1787: 1784: 1778: 1772: 1767: 1763: 1759: 1753: 1747: 1742: 1738: 1734: 1728: 1725: 1722: 1716: 1711: 1707: 1703: 1697: 1691: 1686: 1682: 1674: 1656: 1650: 1645: 1641: 1637: 1631: 1625: 1620: 1616: 1612: 1606: 1603: 1597: 1592: 1588: 1579: 1576: 1575: 1571: 1568: 1566: 1565: 1562: 1548: 1543: 1540: 1535: 1531: 1526: 1522: 1519: 1499: 1494: 1491: 1486: 1482: 1477: 1473: 1470: 1442: 1440: 1438: 1434: 1430: 1424: 1416: 1400: 1395: 1392: 1389: 1385: 1381: 1376: 1366: 1362: 1338: 1328: 1324: 1316: 1312: 1305: 1301: 1296: 1288: 1287: 1286: 1276: 1271: 1253: 1228: 1224: 1220: 1215: 1211: 1207: 1205: 1198: 1190: 1187: 1184: 1172: 1169: 1166: 1162: 1158: 1156: 1149: 1139: 1135: 1122: 1118: 1114: 1109: 1105: 1101: 1099: 1092: 1089: 1086: 1082: 1070: 1069: 1068: 1066: 1060: 1052: 1050: 1033: 1030: 1027: 1021: 1018: 998: 995: 992: 989: 986: 983: 980: 977: 971: 968: 962: 959: 950: 936: 933: 930: 910: 907: 904: 901: 881: 858: 855: 852: 849: 846: 839: 838: 837: 823: 815: 799: 796: 793: 790: 787: 782: 778: 774: 771: 768: 763: 759: 749: 747: 743: 738: 736: 732: 728: 724: 718: 710: 708: 691: 688: 685: 676: 673: 670: 664: 659: 655: 651: 646: 642: 619: 615: 611: 608: 605: 602: 599: 594: 590: 586: 581: 573: 570: 567: 556: 540: 537: 531: 528: 522: 519: 499: 496: 493: 490: 487: 477: 469: 464: 462: 460: 456: 444: 428: 425: 422: 419: 414: 410: 406: 403: 400: 395: 391: 368: 364: 360: 357: 354: 351: 348: 343: 339: 335: 330: 322: 319: 316: 305: 301: 297: 293: 290: =  289: 285: 281: 277: 273: 269: 265: 262: 259:relating one 258: 254: 250: 230: 227: 224: 221: 216: 212: 208: 205: 202: 197: 193: 172: 169: 164: 160: 156: 151: 147: 138: 119: 116: 113: 110: 107: 104: 101: 95: 89: 86: 83: 60: 52: 47: 41: 37: 33: 19: 3741: 3721: 3701: 3665: 3662:Arto Salomaa 3647: 3638: 3621: 3597: 3590: 3565: 3561: 3551: 3526: 3518: 3507:. Retrieved 3503: 3493: 3482:. Retrieved 3478: 3469: 3458:. Retrieved 3455:www.math.com 3454: 3445: 3434:. Retrieved 3430: 3421: 3410:. Retrieved 3406: 3397: 3385: 3373: 3351:Downing 2003 3347:Shirali 2002 3341: 3297: 3188: 2923: 2917: 2851:of the form 2843: 2827: 2817: 2811: 2730: 2726: 2721: 2716: 2714: 2554: 2549: 2542: 2435: 2431: 2427: 2423: 2418: 2415: 1446: 1432: 1428: 1426: 1272: 1249: 1062: 951: 873: 750: 739: 720: 479: 299: 295: 291: 287: 275: 271: 270:, such that 267: 263: 252: 246: 135:lies on the 73:, the point 3568:(34): 189. 3533:McGraw-Hill 2816:. In fact, 1275:associative 1252:commutative 742:integration 455:equals sign 449:instead of 249:mathematics 137:unit circle 3790:Categories 3509:2019-12-01 3504:Purplemath 3484:2019-12-01 3460:2019-12-01 3436:2019-12-01 3412:2019-12-01 3328:References 1437:logarithms 816:values of 474:See also: 461:equality. 443:triple bar 3365:Citations 3300:equations 3271:∗ 3252:∗ 3239:∗ 3230:∗ 3212:∗ 3203:∗ 3162:∗ 3150:∀ 3134:∗ 3122:∀ 3112:∗ 3103:∗ 3085:∗ 3076:∗ 3052:∀ 3008:… 2992:∀ 2956:… 2875:… 2859:∀ 2770:⁡ 2685:⁡ 2661:⁡ 2630:⁡ 2606:⁡ 2578:⁡ 2512:⁡ 2488:⁡ 2460:⁡ 2372:⁡ 2295:⁡ 2215:⁡ 2180:⁡ 2155:⁡ 2114:⁡ 2079:⁡ 2033:− 2015:⁡ 2002:− 1990:⁡ 1933:⁡ 1893:⁡ 1880:− 1868:⁡ 1773:⁡ 1748:⁡ 1726:⋅ 1717:⁡ 1692:⁡ 1651:⁡ 1626:⁡ 1598:⁡ 1541:⁡ 1492:⁡ 1435:, relate 1393:⋅ 1221:⋅ 1188:⋅ 1170:⋅ 1115:⋅ 1022:⁡ 999:θ 996:⁡ 990:θ 987:⁡ 972:θ 963:⁡ 931:θ 902:θ 882:θ 853:θ 850:⁡ 824:θ 791:θ 788:⁡ 772:θ 769:⁡ 689:− 652:− 529:− 423:θ 420:⁡ 404:θ 401:⁡ 304:functions 280:variables 225:θ 222:⁡ 206:θ 203:⁡ 120:θ 117:⁡ 108:θ 105:⁡ 61:θ 3777:Archived 3664:(eds.). 3306:See also 2543:Typical 1816:quotient 1572:Example 1433:log laws 1266:whereas 735:triangle 257:equality 253:identity 185:. Thus, 3692:Sources 3637:(ed.). 3582:3602492 3546:, p. 21 2849:formula 1577:product 1569:Formula 1512:and/or 1065:integer 555:algebra 445:symbol 3749:  3728:  3709:  3676:  3605:  3580:  3539:  3039:monoid 3035:axioms 2915:where 1262:, but 727:angles 453:, the 255:is an 3670:EATCS 3578:JSTOR 3333:Notes 3037:of a 2935:than 2929:terms 2058:power 1268:3 = 9 1264:2 = 8 251:, an 38:, or 3747:ISBN 3726:ISBN 3707:ISBN 3674:ISBN 3603:ISBN 3537:ISBN 2927:are 2921:and 2828:The 2823:even 2430:and 2375:1000 2344:1000 2246:root 1281:and 1258:and 814:real 634:and 512:and 383:and 298:and 274:and 3570:doi 2761:log 2676:log 2652:log 2621:log 2597:log 2569:log 2503:log 2479:log 2451:log 2394:1.5 2363:log 2332:log 2286:log 2257:log 2206:log 2171:log 2146:log 2105:log 2070:log 2006:log 1981:log 1949:log 1924:log 1884:log 1859:log 1827:log 1764:log 1739:log 1708:log 1698:243 1683:log 1642:log 1617:log 1589:log 1532:log 1483:log 1431:or 1019:tan 993:cos 984:sin 960:sin 847:cos 779:cos 760:sin 411:sin 392:cos 247:In 213:sin 194:cos 114:sin 102:cos 3792:: 3668:. 3660:; 3656:; 3629:; 3613:, 3576:. 3564:. 3560:. 3535:, 3502:. 3477:. 3453:. 3429:. 3405:. 2836:. 2625:10 2601:10 2367:10 2336:10 2161:64 1996:64 1965:64 1939:16 1779:27 1729:27 1313::= 1270:. 949:. 34:, 3755:. 3734:. 3715:. 3682:. 3611:. 3584:. 3572:: 3566:2 3512:. 3487:. 3463:. 3439:. 3415:. 3283:. 3280:x 3277:= 3274:x 3268:1 3264:, 3261:x 3258:= 3255:1 3249:x 3245:, 3242:z 3236:) 3233:y 3227:x 3224:( 3221:= 3218:) 3215:z 3209:y 3206:( 3200:x 3174:, 3171:x 3168:= 3165:x 3159:1 3156:: 3153:x 3146:, 3143:x 3140:= 3137:1 3131:x 3128:: 3125:x 3118:, 3115:z 3109:) 3106:y 3100:x 3097:( 3094:= 3091:) 3088:z 3082:y 3079:( 3073:x 3070:: 3067:z 3064:, 3061:y 3058:, 3055:x 3019:n 3015:x 3011:, 3005:, 3000:1 2996:x 2972:. 2967:n 2963:x 2959:, 2953:, 2948:1 2944:x 2924:t 2918:s 2903:, 2900:t 2897:= 2894:s 2891:: 2886:n 2882:x 2878:, 2872:, 2867:1 2863:x 2786:. 2779:) 2776:x 2773:( 2765:b 2756:1 2751:x 2747:= 2744:b 2731:b 2727:x 2725:( 2722:b 2717:x 2700:. 2694:) 2691:b 2688:( 2680:e 2670:) 2667:x 2664:( 2656:e 2645:= 2639:) 2636:b 2633:( 2615:) 2612:x 2609:( 2590:= 2587:) 2584:x 2581:( 2573:b 2555:b 2550:e 2527:. 2521:) 2518:b 2515:( 2507:k 2497:) 2494:x 2491:( 2483:k 2472:= 2469:) 2466:x 2463:( 2455:b 2436:k 2432:b 2428:x 2424:x 2422:( 2419:b 2391:= 2386:2 2383:3 2378:= 2357:2 2354:1 2349:= 2308:p 2304:) 2301:x 2298:( 2290:b 2279:= 2273:p 2269:x 2261:b 2230:6 2227:= 2224:) 2221:2 2218:( 2210:2 2202:6 2199:= 2196:) 2191:6 2187:2 2183:( 2175:2 2167:= 2164:) 2158:( 2150:2 2123:) 2120:x 2117:( 2109:b 2101:p 2098:= 2095:) 2090:p 2086:x 2082:( 2074:b 2042:4 2039:= 2036:2 2030:6 2027:= 2024:) 2021:4 2018:( 2010:2 1999:) 1993:( 1985:2 1977:= 1973:) 1968:4 1960:( 1953:2 1945:= 1942:) 1936:( 1928:2 1902:) 1899:y 1896:( 1888:b 1877:) 1874:x 1871:( 1863:b 1855:= 1851:) 1846:y 1843:x 1838:( 1831:b 1800:5 1797:= 1794:3 1791:+ 1788:2 1785:= 1782:) 1776:( 1768:3 1760:+ 1757:) 1754:9 1751:( 1743:3 1735:= 1732:) 1723:9 1720:( 1712:3 1704:= 1701:) 1695:( 1687:3 1660:) 1657:y 1654:( 1646:b 1638:+ 1635:) 1632:x 1629:( 1621:b 1613:= 1610:) 1607:y 1604:x 1601:( 1593:b 1549:, 1544:y 1536:b 1527:b 1523:= 1520:y 1500:, 1495:x 1487:b 1478:b 1474:= 1471:x 1461:p 1457:p 1453:p 1449:p 1401:. 1396:q 1390:p 1386:b 1382:= 1377:q 1373:) 1367:p 1363:b 1359:( 1339:, 1334:) 1329:q 1325:p 1321:( 1317:b 1306:q 1302:p 1297:b 1229:n 1225:c 1216:n 1212:b 1208:= 1199:n 1195:) 1191:c 1185:b 1182:( 1173:n 1167:m 1163:b 1159:= 1150:n 1146:) 1140:m 1136:b 1132:( 1123:n 1119:b 1110:m 1106:b 1102:= 1093:n 1090:+ 1087:m 1083:b 1037:) 1034:y 1031:+ 1028:x 1025:( 981:2 978:= 975:) 969:2 966:( 937:2 934:= 911:, 908:0 905:= 859:1 856:= 800:, 797:1 794:= 783:2 775:+ 764:2 695:) 692:b 686:a 683:( 680:) 677:b 674:+ 671:a 668:( 665:= 660:2 656:b 647:2 643:a 620:2 616:b 612:+ 609:b 606:a 603:2 600:+ 595:2 591:a 587:= 582:2 578:) 574:b 571:+ 568:a 565:( 541:0 538:= 535:) 532:a 526:( 523:+ 520:a 500:a 497:= 494:0 491:+ 488:a 451:= 447:≡ 429:1 426:= 415:2 407:+ 396:2 369:2 365:b 361:+ 358:b 355:a 352:2 349:+ 344:2 340:a 336:= 331:2 327:) 323:b 320:+ 317:a 314:( 300:B 296:A 292:B 288:A 276:B 272:A 268:B 264:A 243:. 231:1 228:= 217:2 209:+ 198:2 173:1 170:= 165:2 161:y 157:+ 152:2 148:x 123:) 111:, 99:( 96:= 93:) 90:y 87:, 84:x 81:( 42:. 20:)

Index

Mathematical identities
identity element
identity function
identity matrix

Pythagorean identity
unit circle
mathematics
equality
mathematical expression
variables
domain of discourse
functions
triple bar
equals sign
universally quantified
Factorization § Recognizable patterns
algebra
List of trigonometric identities
trigonometric identities
angles
triangle identities
triangle
integration
substitution rule with a trigonometric function
real
Exponentiation
integer
commutative
associative

Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.