constants.html 31 KB

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  25. <div class="section">
  26. <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  27. <a name="math_toolkit.constants"></a><a class="link" href="constants.html" title="The Mathematical Constants">The Mathematical Constants</a>
  28. </h2></div></div></div>
  29. <p>
  30. This section lists the mathematical constants, their use(s) (and sometimes
  31. rationale for their inclusion).
  32. </p>
  33. <div class="table">
  34. <a name="math_toolkit.constants.mathematical_constants"></a><p class="title"><b>Table&#160;4.1.&#160;Mathematical Constants</b></p>
  35. <div class="table-contents"><table class="table" summary="Mathematical Constants">
  36. <colgroup>
  37. <col>
  38. <col>
  39. <col>
  40. <col>
  41. </colgroup>
  42. <thead><tr>
  43. <th>
  44. <p>
  45. name
  46. </p>
  47. </th>
  48. <th>
  49. <p>
  50. formula
  51. </p>
  52. </th>
  53. <th>
  54. <p>
  55. Value (6 decimals)
  56. </p>
  57. </th>
  58. <th>
  59. <p>
  60. Uses and Rationale
  61. </p>
  62. </th>
  63. </tr></thead>
  64. <tbody>
  65. <tr>
  66. <td>
  67. <p>
  68. <span class="bold"><strong>Rational fractions</strong></span>
  69. </p>
  70. </td>
  71. <td>
  72. </td>
  73. <td>
  74. </td>
  75. <td>
  76. </td>
  77. </tr>
  78. <tr>
  79. <td>
  80. <p>
  81. half
  82. </p>
  83. </td>
  84. <td>
  85. <p>
  86. 1/2
  87. </p>
  88. </td>
  89. <td>
  90. <p>
  91. 0.5
  92. </p>
  93. </td>
  94. <td>
  95. </td>
  96. </tr>
  97. <tr>
  98. <td>
  99. <p>
  100. third
  101. </p>
  102. </td>
  103. <td>
  104. <p>
  105. 1/3
  106. </p>
  107. </td>
  108. <td>
  109. <p>
  110. 0.333333
  111. </p>
  112. </td>
  113. <td>
  114. </td>
  115. </tr>
  116. <tr>
  117. <td>
  118. <p>
  119. two_thirds
  120. </p>
  121. </td>
  122. <td>
  123. <p>
  124. 2/3
  125. </p>
  126. </td>
  127. <td>
  128. <p>
  129. 0.66667
  130. </p>
  131. </td>
  132. <td>
  133. </td>
  134. </tr>
  135. <tr>
  136. <td>
  137. <p>
  138. three_quarters
  139. </p>
  140. </td>
  141. <td>
  142. <p>
  143. 3/4
  144. </p>
  145. </td>
  146. <td>
  147. <p>
  148. 0.75
  149. </p>
  150. </td>
  151. <td>
  152. </td>
  153. </tr>
  154. <tr>
  155. <td>
  156. <p>
  157. <span class="bold"><strong>two and related</strong></span>
  158. </p>
  159. </td>
  160. <td>
  161. </td>
  162. <td>
  163. </td>
  164. <td>
  165. </td>
  166. </tr>
  167. <tr>
  168. <td>
  169. <p>
  170. root_two
  171. </p>
  172. </td>
  173. <td>
  174. <p>
  175. &#8730;2
  176. </p>
  177. </td>
  178. <td>
  179. <p>
  180. 1.41421
  181. </p>
  182. </td>
  183. <td>
  184. <p>
  185. Equivalent to POSIX constant M_SQRT2
  186. </p>
  187. </td>
  188. </tr>
  189. <tr>
  190. <td>
  191. <p>
  192. root_three
  193. </p>
  194. </td>
  195. <td>
  196. <p>
  197. &#8730;3
  198. </p>
  199. </td>
  200. <td>
  201. <p>
  202. 1.73205
  203. </p>
  204. </td>
  205. <td>
  206. </td>
  207. </tr>
  208. <tr>
  209. <td>
  210. <p>
  211. half_root_two
  212. </p>
  213. </td>
  214. <td>
  215. <p>
  216. &#8730;2 /2
  217. </p>
  218. </td>
  219. <td>
  220. <p>
  221. 0.707106
  222. </p>
  223. </td>
  224. <td>
  225. </td>
  226. </tr>
  227. <tr>
  228. <td>
  229. <p>
  230. ln_two
  231. </p>
  232. </td>
  233. <td>
  234. <p>
  235. ln(2)
  236. </p>
  237. </td>
  238. <td>
  239. <p>
  240. 0.693147
  241. </p>
  242. </td>
  243. <td>
  244. <p>
  245. Equivalent to POSIX constant M_LN2
  246. </p>
  247. </td>
  248. </tr>
  249. <tr>
  250. <td>
  251. <p>
  252. ln_ten
  253. </p>
  254. </td>
  255. <td>
  256. <p>
  257. ln(10)
  258. </p>
  259. </td>
  260. <td>
  261. <p>
  262. 2.30258
  263. </p>
  264. </td>
  265. <td>
  266. <p>
  267. Equivalent to POSIX constant M_LN10
  268. </p>
  269. </td>
  270. </tr>
  271. <tr>
  272. <td>
  273. <p>
  274. ln_ln_two
  275. </p>
  276. </td>
  277. <td>
  278. <p>
  279. ln(ln(2))
  280. </p>
  281. </td>
  282. <td>
  283. <p>
  284. -0.366512
  285. </p>
  286. </td>
  287. <td>
  288. <p>
  289. Gumbel distribution median
  290. </p>
  291. </td>
  292. </tr>
  293. <tr>
  294. <td>
  295. <p>
  296. root_ln_four
  297. </p>
  298. </td>
  299. <td>
  300. <p>
  301. &#8730;ln(4)
  302. </p>
  303. </td>
  304. <td>
  305. <p>
  306. 1.177410
  307. </p>
  308. </td>
  309. <td>
  310. </td>
  311. </tr>
  312. <tr>
  313. <td>
  314. <p>
  315. one_div_root_two
  316. </p>
  317. </td>
  318. <td>
  319. <p>
  320. 1/&#8730;2
  321. </p>
  322. </td>
  323. <td>
  324. <p>
  325. 0.707106
  326. </p>
  327. </td>
  328. <td>
  329. <p>
  330. Equivalent to POSIX constant M_SQRT1_2
  331. </p>
  332. </td>
  333. </tr>
  334. <tr>
  335. <td>
  336. <p>
  337. <span class="bold"><strong>&#960; and related</strong></span>
  338. </p>
  339. </td>
  340. <td>
  341. </td>
  342. <td>
  343. </td>
  344. <td>
  345. </td>
  346. </tr>
  347. <tr>
  348. <td>
  349. <p>
  350. pi
  351. </p>
  352. </td>
  353. <td>
  354. <p>
  355. pi
  356. </p>
  357. </td>
  358. <td>
  359. <p>
  360. 3.14159
  361. </p>
  362. </td>
  363. <td>
  364. <p>
  365. Ubiquitous. Archimedes constant <a href="http://en.wikipedia.org/wiki/Pi" target="_top">&#960;</a>.
  366. Equivalent to POSIX constant M_PI
  367. </p>
  368. </td>
  369. </tr>
  370. <tr>
  371. <td>
  372. <p>
  373. half_pi
  374. </p>
  375. </td>
  376. <td>
  377. <p>
  378. &#960;/2
  379. </p>
  380. </td>
  381. <td>
  382. <p>
  383. 1.570796
  384. </p>
  385. </td>
  386. <td>
  387. <p>
  388. Equivalent to POSIX constant M_PI2
  389. </p>
  390. </td>
  391. </tr>
  392. <tr>
  393. <td>
  394. <p>
  395. third_pi
  396. </p>
  397. </td>
  398. <td>
  399. <p>
  400. &#960;/3
  401. </p>
  402. </td>
  403. <td>
  404. <p>
  405. 1.04719
  406. </p>
  407. </td>
  408. <td>
  409. </td>
  410. </tr>
  411. <tr>
  412. <td>
  413. <p>
  414. quarter_pi
  415. </p>
  416. </td>
  417. <td>
  418. <p>
  419. &#960;/4
  420. </p>
  421. </td>
  422. <td>
  423. <p>
  424. 0.78539816
  425. </p>
  426. </td>
  427. <td>
  428. <p>
  429. Equivalent to POSIX constant M_PI_4
  430. </p>
  431. </td>
  432. </tr>
  433. <tr>
  434. <td>
  435. <p>
  436. sixth_pi
  437. </p>
  438. </td>
  439. <td>
  440. <p>
  441. &#960;/6
  442. </p>
  443. </td>
  444. <td>
  445. <p>
  446. 0.523598
  447. </p>
  448. </td>
  449. <td>
  450. </td>
  451. </tr>
  452. <tr>
  453. <td>
  454. <p>
  455. two_pi
  456. </p>
  457. </td>
  458. <td>
  459. <p>
  460. 2&#960;
  461. </p>
  462. </td>
  463. <td>
  464. <p>
  465. 6.28318
  466. </p>
  467. </td>
  468. <td>
  469. <p>
  470. Many uses, most simply, circumference of a circle
  471. </p>
  472. </td>
  473. </tr>
  474. <tr>
  475. <td>
  476. <p>
  477. two_thirds_pi
  478. </p>
  479. </td>
  480. <td>
  481. <p>
  482. 2/3 &#960;
  483. </p>
  484. </td>
  485. <td>
  486. <p>
  487. 2.09439
  488. </p>
  489. </td>
  490. <td>
  491. <p>
  492. <a href="http://en.wikipedia.org/wiki/Sphere#Volume_of_a_sphere" target="_top">volume
  493. of a hemi-sphere</a> = 4/3 &#960; r&#179;
  494. </p>
  495. </td>
  496. </tr>
  497. <tr>
  498. <td>
  499. <p>
  500. three_quarters_pi
  501. </p>
  502. </td>
  503. <td>
  504. <p>
  505. 3/4 &#960;
  506. </p>
  507. </td>
  508. <td>
  509. <p>
  510. 2.35619
  511. </p>
  512. </td>
  513. <td>
  514. <p>
  515. = 3/4 &#960;
  516. </p>
  517. </td>
  518. </tr>
  519. <tr>
  520. <td>
  521. <p>
  522. four_thirds_pi
  523. </p>
  524. </td>
  525. <td>
  526. <p>
  527. 4/3 &#960;
  528. </p>
  529. </td>
  530. <td>
  531. <p>
  532. 4.18879
  533. </p>
  534. </td>
  535. <td>
  536. <p>
  537. <a href="http://en.wikipedia.org/wiki/Sphere#Volume_of_a_sphere" target="_top">volume
  538. of a sphere</a> = 4/3 &#960; r&#179;
  539. </p>
  540. </td>
  541. </tr>
  542. <tr>
  543. <td>
  544. <p>
  545. one_div_two_pi
  546. </p>
  547. </td>
  548. <td>
  549. <p>
  550. 1/(2&#960;)
  551. </p>
  552. </td>
  553. <td>
  554. <p>
  555. 1.59155
  556. </p>
  557. </td>
  558. <td>
  559. <p>
  560. Widely used
  561. </p>
  562. </td>
  563. </tr>
  564. <tr>
  565. <td>
  566. <p>
  567. root_pi
  568. </p>
  569. </td>
  570. <td>
  571. <p>
  572. &#8730;&#960;
  573. </p>
  574. </td>
  575. <td>
  576. <p>
  577. 1.77245
  578. </p>
  579. </td>
  580. <td>
  581. <p>
  582. Widely used
  583. </p>
  584. </td>
  585. </tr>
  586. <tr>
  587. <td>
  588. <p>
  589. root_half_pi
  590. </p>
  591. </td>
  592. <td>
  593. <p>
  594. &#8730; &#960;/2
  595. </p>
  596. </td>
  597. <td>
  598. <p>
  599. 1.25331
  600. </p>
  601. </td>
  602. <td>
  603. <p>
  604. Widely used
  605. </p>
  606. </td>
  607. </tr>
  608. <tr>
  609. <td>
  610. <p>
  611. root_two_pi
  612. </p>
  613. </td>
  614. <td>
  615. <p>
  616. &#8730; &#960;*2
  617. </p>
  618. </td>
  619. <td>
  620. <p>
  621. 2.50662
  622. </p>
  623. </td>
  624. <td>
  625. <p>
  626. Widely used
  627. </p>
  628. </td>
  629. </tr>
  630. <tr>
  631. <td>
  632. <p>
  633. one_div_pi
  634. </p>
  635. </td>
  636. <td>
  637. <p>
  638. 1/&#960;
  639. </p>
  640. </td>
  641. <td>
  642. <p>
  643. 0.31830988
  644. </p>
  645. </td>
  646. <td>
  647. <p>
  648. Equivalent to POSIX constant M_1_PI
  649. </p>
  650. </td>
  651. </tr>
  652. <tr>
  653. <td>
  654. <p>
  655. two_div_pi
  656. </p>
  657. </td>
  658. <td>
  659. <p>
  660. 2/&#960;
  661. </p>
  662. </td>
  663. <td>
  664. <p>
  665. 0.63661977
  666. </p>
  667. </td>
  668. <td>
  669. <p>
  670. Equivalent to POSIX constant M_2_PI
  671. </p>
  672. </td>
  673. </tr>
  674. <tr>
  675. <td>
  676. <p>
  677. one_div_root_pi
  678. </p>
  679. </td>
  680. <td>
  681. <p>
  682. 1/&#8730;&#960;
  683. </p>
  684. </td>
  685. <td>
  686. <p>
  687. 0.564189
  688. </p>
  689. </td>
  690. <td>
  691. </td>
  692. </tr>
  693. <tr>
  694. <td>
  695. <p>
  696. two_div_root_pi
  697. </p>
  698. </td>
  699. <td>
  700. <p>
  701. 2/&#8730;&#960;
  702. </p>
  703. </td>
  704. <td>
  705. <p>
  706. 1.128379
  707. </p>
  708. </td>
  709. <td>
  710. <p>
  711. Equivalent to POSIX constant M_2_SQRTPI
  712. </p>
  713. </td>
  714. </tr>
  715. <tr>
  716. <td>
  717. <p>
  718. one_div_root_two_pi
  719. </p>
  720. </td>
  721. <td>
  722. <p>
  723. 1/&#8730;(2&#960;)
  724. </p>
  725. </td>
  726. <td>
  727. <p>
  728. 0.398942
  729. </p>
  730. </td>
  731. <td>
  732. </td>
  733. </tr>
  734. <tr>
  735. <td>
  736. <p>
  737. root_one_div_pi
  738. </p>
  739. </td>
  740. <td>
  741. <p>
  742. &#8730;(1/&#960;
  743. </p>
  744. </td>
  745. <td>
  746. <p>
  747. 0.564189
  748. </p>
  749. </td>
  750. <td>
  751. </td>
  752. </tr>
  753. <tr>
  754. <td>
  755. <p>
  756. pi_minus_three
  757. </p>
  758. </td>
  759. <td>
  760. <p>
  761. &#960;-3
  762. </p>
  763. </td>
  764. <td>
  765. <p>
  766. 0.141593
  767. </p>
  768. </td>
  769. <td>
  770. </td>
  771. </tr>
  772. <tr>
  773. <td>
  774. <p>
  775. four_minus_pi
  776. </p>
  777. </td>
  778. <td>
  779. <p>
  780. 4 -&#960;
  781. </p>
  782. </td>
  783. <td>
  784. <p>
  785. 0.858407
  786. </p>
  787. </td>
  788. <td>
  789. </td>
  790. </tr>
  791. <tr>
  792. <td>
  793. <p>
  794. pi_pow_e
  795. </p>
  796. </td>
  797. <td>
  798. <p>
  799. &#960;<sup>e</sup>
  800. </p>
  801. </td>
  802. <td>
  803. <p>
  804. 22.4591
  805. </p>
  806. </td>
  807. <td>
  808. </td>
  809. </tr>
  810. <tr>
  811. <td>
  812. <p>
  813. pi_sqr
  814. </p>
  815. </td>
  816. <td>
  817. <p>
  818. &#960;<sup>2</sup>
  819. </p>
  820. </td>
  821. <td>
  822. <p>
  823. 9.86960
  824. </p>
  825. </td>
  826. <td>
  827. </td>
  828. </tr>
  829. <tr>
  830. <td>
  831. <p>
  832. pi_sqr_div_six
  833. </p>
  834. </td>
  835. <td>
  836. <p>
  837. &#960;<sup>2</sup>/6
  838. </p>
  839. </td>
  840. <td>
  841. <p>
  842. 1.64493
  843. </p>
  844. </td>
  845. <td>
  846. </td>
  847. </tr>
  848. <tr>
  849. <td>
  850. <p>
  851. pi_cubed
  852. </p>
  853. </td>
  854. <td>
  855. <p>
  856. &#960;<sup>3</sup>
  857. </p>
  858. </td>
  859. <td>
  860. <p>
  861. 31.00627
  862. </p>
  863. </td>
  864. <td>
  865. </td>
  866. </tr>
  867. <tr>
  868. <td>
  869. <p>
  870. cbrt_pi
  871. </p>
  872. </td>
  873. <td>
  874. <p>
  875. &#8730;<sup>3</sup> &#960;
  876. </p>
  877. </td>
  878. <td>
  879. <p>
  880. 1.46459
  881. </p>
  882. </td>
  883. <td>
  884. </td>
  885. </tr>
  886. <tr>
  887. <td>
  888. <p>
  889. one_div_cbrt_pi
  890. </p>
  891. </td>
  892. <td>
  893. <p>
  894. 1/&#8730;<sup>3</sup> &#960;
  895. </p>
  896. </td>
  897. <td>
  898. <p>
  899. 0.682784
  900. </p>
  901. </td>
  902. <td>
  903. </td>
  904. </tr>
  905. <tr>
  906. <td>
  907. <p>
  908. <span class="bold"><strong>Euler's e and related</strong></span>
  909. </p>
  910. </td>
  911. <td>
  912. </td>
  913. <td>
  914. </td>
  915. <td>
  916. </td>
  917. </tr>
  918. <tr>
  919. <td>
  920. <p>
  921. e
  922. </p>
  923. </td>
  924. <td>
  925. <p>
  926. e
  927. </p>
  928. </td>
  929. <td>
  930. <p>
  931. 2.71828
  932. </p>
  933. </td>
  934. <td>
  935. <p>
  936. <a href="http://en.wikipedia.org/wiki/E_(mathematical_constant)" target="_top">Euler's
  937. constant e</a>, equivalent to POSIX constant M_E
  938. </p>
  939. </td>
  940. </tr>
  941. <tr>
  942. <td>
  943. <p>
  944. exp_minus_half
  945. </p>
  946. </td>
  947. <td>
  948. <p>
  949. e <sup>-1/2</sup>
  950. </p>
  951. </td>
  952. <td>
  953. <p>
  954. 0.606530
  955. </p>
  956. </td>
  957. <td>
  958. </td>
  959. </tr>
  960. <tr>
  961. <td>
  962. <p>
  963. e_pow_pi
  964. </p>
  965. </td>
  966. <td>
  967. <p>
  968. e <sup>&#960;</sup>
  969. </p>
  970. </td>
  971. <td>
  972. <p>
  973. 23.14069
  974. </p>
  975. </td>
  976. <td>
  977. </td>
  978. </tr>
  979. <tr>
  980. <td>
  981. <p>
  982. root_e
  983. </p>
  984. </td>
  985. <td>
  986. <p>
  987. &#8730; e
  988. </p>
  989. </td>
  990. <td>
  991. <p>
  992. 1.64872
  993. </p>
  994. </td>
  995. <td>
  996. </td>
  997. </tr>
  998. <tr>
  999. <td>
  1000. <p>
  1001. log10_e
  1002. </p>
  1003. </td>
  1004. <td>
  1005. <p>
  1006. log10(e)
  1007. </p>
  1008. </td>
  1009. <td>
  1010. <p>
  1011. 0.434294
  1012. </p>
  1013. </td>
  1014. <td>
  1015. <p>
  1016. Equivalent to POSIX constant M_LOG10E
  1017. </p>
  1018. </td>
  1019. </tr>
  1020. <tr>
  1021. <td>
  1022. <p>
  1023. one_div_log10_e
  1024. </p>
  1025. </td>
  1026. <td>
  1027. <p>
  1028. 1/log10(e)
  1029. </p>
  1030. </td>
  1031. <td>
  1032. <p>
  1033. 2.30258
  1034. </p>
  1035. </td>
  1036. <td>
  1037. </td>
  1038. </tr>
  1039. <tr>
  1040. <td>
  1041. <p>
  1042. log2_e
  1043. </p>
  1044. </td>
  1045. <td>
  1046. <p>
  1047. log<sub>2</sub>(e)
  1048. </p>
  1049. </td>
  1050. <td>
  1051. <p>
  1052. 1.442695
  1053. </p>
  1054. </td>
  1055. <td>
  1056. <p>
  1057. This is the same as 1/ln(2) and is equivalent to POSIX constant M_LOG2E
  1058. </p>
  1059. </td>
  1060. </tr>
  1061. <tr>
  1062. <td>
  1063. <p>
  1064. <span class="bold"><strong>Trigonometric</strong></span>
  1065. </p>
  1066. </td>
  1067. <td>
  1068. </td>
  1069. <td>
  1070. </td>
  1071. <td>
  1072. </td>
  1073. </tr>
  1074. <tr>
  1075. <td>
  1076. <p>
  1077. degree
  1078. </p>
  1079. </td>
  1080. <td>
  1081. <p>
  1082. radians = &#960; / 180
  1083. </p>
  1084. </td>
  1085. <td>
  1086. <p>
  1087. 0.017453
  1088. </p>
  1089. </td>
  1090. <td>
  1091. </td>
  1092. </tr>
  1093. <tr>
  1094. <td>
  1095. <p>
  1096. radian
  1097. </p>
  1098. </td>
  1099. <td>
  1100. <p>
  1101. degrees = 180 / &#960;
  1102. </p>
  1103. </td>
  1104. <td>
  1105. <p>
  1106. 57.2957
  1107. </p>
  1108. </td>
  1109. <td>
  1110. </td>
  1111. </tr>
  1112. <tr>
  1113. <td>
  1114. <p>
  1115. sin_one
  1116. </p>
  1117. </td>
  1118. <td>
  1119. <p>
  1120. sin(1)
  1121. </p>
  1122. </td>
  1123. <td>
  1124. <p>
  1125. 0.841470
  1126. </p>
  1127. </td>
  1128. <td>
  1129. </td>
  1130. </tr>
  1131. <tr>
  1132. <td>
  1133. <p>
  1134. cos_one
  1135. </p>
  1136. </td>
  1137. <td>
  1138. <p>
  1139. cos(1)
  1140. </p>
  1141. </td>
  1142. <td>
  1143. <p>
  1144. 0.54030
  1145. </p>
  1146. </td>
  1147. <td>
  1148. </td>
  1149. </tr>
  1150. <tr>
  1151. <td>
  1152. <p>
  1153. sinh_one
  1154. </p>
  1155. </td>
  1156. <td>
  1157. <p>
  1158. sinh(1)
  1159. </p>
  1160. </td>
  1161. <td>
  1162. <p>
  1163. 1.17520
  1164. </p>
  1165. </td>
  1166. <td>
  1167. </td>
  1168. </tr>
  1169. <tr>
  1170. <td>
  1171. <p>
  1172. cosh_one
  1173. </p>
  1174. </td>
  1175. <td>
  1176. <p>
  1177. cosh(1)
  1178. </p>
  1179. </td>
  1180. <td>
  1181. <p>
  1182. 1.54308
  1183. </p>
  1184. </td>
  1185. <td>
  1186. </td>
  1187. </tr>
  1188. <tr>
  1189. <td>
  1190. <p>
  1191. <span class="bold"><strong>Phi</strong></span>
  1192. </p>
  1193. </td>
  1194. <td>
  1195. <p>
  1196. Phidias golden ratio
  1197. </p>
  1198. </td>
  1199. <td>
  1200. <p>
  1201. <a href="http://en.wikipedia.org/wiki/Golden_ratio" target="_top">Phidias golden
  1202. ratio</a>
  1203. </p>
  1204. </td>
  1205. <td>
  1206. </td>
  1207. </tr>
  1208. <tr>
  1209. <td>
  1210. <p>
  1211. phi
  1212. </p>
  1213. </td>
  1214. <td>
  1215. <p>
  1216. (1 + &#8730;5) /2
  1217. </p>
  1218. </td>
  1219. <td>
  1220. <p>
  1221. 1.61803
  1222. </p>
  1223. </td>
  1224. <td>
  1225. <p>
  1226. finance
  1227. </p>
  1228. </td>
  1229. </tr>
  1230. <tr>
  1231. <td>
  1232. <p>
  1233. ln_phi
  1234. </p>
  1235. </td>
  1236. <td>
  1237. <p>
  1238. ln(&#966;)
  1239. </p>
  1240. </td>
  1241. <td>
  1242. <p>
  1243. 0.48121
  1244. </p>
  1245. </td>
  1246. <td>
  1247. </td>
  1248. </tr>
  1249. <tr>
  1250. <td>
  1251. <p>
  1252. one_div_ln_phi
  1253. </p>
  1254. </td>
  1255. <td>
  1256. <p>
  1257. 1/ln(&#966;)
  1258. </p>
  1259. </td>
  1260. <td>
  1261. <p>
  1262. 2.07808
  1263. </p>
  1264. </td>
  1265. <td>
  1266. </td>
  1267. </tr>
  1268. <tr>
  1269. <td>
  1270. <p>
  1271. <span class="bold"><strong>Euler's Gamma</strong></span>
  1272. </p>
  1273. </td>
  1274. <td>
  1275. </td>
  1276. <td>
  1277. </td>
  1278. <td>
  1279. </td>
  1280. </tr>
  1281. <tr>
  1282. <td>
  1283. <p>
  1284. euler
  1285. </p>
  1286. </td>
  1287. <td>
  1288. <p>
  1289. euler
  1290. </p>
  1291. </td>
  1292. <td>
  1293. <p>
  1294. 0.577215
  1295. </p>
  1296. </td>
  1297. <td>
  1298. <p>
  1299. <a href="http://en.wikipedia.org/wiki/Euler%E2%80%93Mascheroni_constant" target="_top">Euler-Mascheroni
  1300. gamma constant</a>
  1301. </p>
  1302. </td>
  1303. </tr>
  1304. <tr>
  1305. <td>
  1306. <p>
  1307. one_div_euler
  1308. </p>
  1309. </td>
  1310. <td>
  1311. <p>
  1312. 1/euler
  1313. </p>
  1314. </td>
  1315. <td>
  1316. <p>
  1317. 1.73245
  1318. </p>
  1319. </td>
  1320. <td>
  1321. </td>
  1322. </tr>
  1323. <tr>
  1324. <td>
  1325. <p>
  1326. euler_sqr
  1327. </p>
  1328. </td>
  1329. <td>
  1330. <p>
  1331. euler<sup>2</sup>
  1332. </p>
  1333. </td>
  1334. <td>
  1335. <p>
  1336. 0.333177
  1337. </p>
  1338. </td>
  1339. <td>
  1340. </td>
  1341. </tr>
  1342. <tr>
  1343. <td>
  1344. <p>
  1345. <span class="bold"><strong>Misc</strong></span>
  1346. </p>
  1347. </td>
  1348. <td>
  1349. </td>
  1350. <td>
  1351. </td>
  1352. <td>
  1353. </td>
  1354. </tr>
  1355. <tr>
  1356. <td>
  1357. <p>
  1358. zeta_two
  1359. </p>
  1360. </td>
  1361. <td>
  1362. <p>
  1363. &#950;(2)
  1364. </p>
  1365. </td>
  1366. <td>
  1367. <p>
  1368. 1.64493
  1369. </p>
  1370. </td>
  1371. <td>
  1372. <p>
  1373. <a href="http://en.wikipedia.org/wiki/Riemann_zeta_function" target="_top">Riemann
  1374. zeta function</a>
  1375. </p>
  1376. </td>
  1377. </tr>
  1378. <tr>
  1379. <td>
  1380. <p>
  1381. zeta_three
  1382. </p>
  1383. </td>
  1384. <td>
  1385. <p>
  1386. &#950;(3)
  1387. </p>
  1388. </td>
  1389. <td>
  1390. <p>
  1391. 1.20205
  1392. </p>
  1393. </td>
  1394. <td>
  1395. <p>
  1396. <a href="http://en.wikipedia.org/wiki/Riemann_zeta_function" target="_top">Riemann
  1397. zeta function</a>
  1398. </p>
  1399. </td>
  1400. </tr>
  1401. <tr>
  1402. <td>
  1403. <p>
  1404. catalan
  1405. </p>
  1406. </td>
  1407. <td>
  1408. <p>
  1409. <span class="emphasis"><em>K</em></span>
  1410. </p>
  1411. </td>
  1412. <td>
  1413. <p>
  1414. 0.915965
  1415. </p>
  1416. </td>
  1417. <td>
  1418. <p>
  1419. <a href="http://mathworld.wolfram.com/CatalansConstant.html" target="_top">Catalan
  1420. (or Glaisher) combinatorial constant</a>
  1421. </p>
  1422. </td>
  1423. </tr>
  1424. <tr>
  1425. <td>
  1426. <p>
  1427. glaisher
  1428. </p>
  1429. </td>
  1430. <td>
  1431. <p>
  1432. <span class="emphasis"><em>A</em></span>
  1433. </p>
  1434. </td>
  1435. <td>
  1436. <p>
  1437. 1.28242
  1438. </p>
  1439. </td>
  1440. <td>
  1441. <p>
  1442. <a href="https://oeis.org/A074962/constant" target="_top">Decimal expansion
  1443. of Glaisher-Kinkelin constant</a>
  1444. </p>
  1445. </td>
  1446. </tr>
  1447. <tr>
  1448. <td>
  1449. <p>
  1450. khinchin
  1451. </p>
  1452. </td>
  1453. <td>
  1454. <p>
  1455. <span class="emphasis"><em>k</em></span>
  1456. </p>
  1457. </td>
  1458. <td>
  1459. <p>
  1460. 2.685452
  1461. </p>
  1462. </td>
  1463. <td>
  1464. <p>
  1465. <a href="https://oeis.org/A002210/constant" target="_top">Decimal expansion
  1466. of Khinchin constant</a>
  1467. </p>
  1468. </td>
  1469. </tr>
  1470. <tr>
  1471. <td>
  1472. <p>
  1473. extreme_value_skewness
  1474. </p>
  1475. </td>
  1476. <td>
  1477. <p>
  1478. 12&#8730;6 &#950;(3)/ &#960;<sup>3</sup>
  1479. </p>
  1480. </td>
  1481. <td>
  1482. <p>
  1483. 1.139547
  1484. </p>
  1485. </td>
  1486. <td>
  1487. <p>
  1488. Extreme value distribution
  1489. </p>
  1490. </td>
  1491. </tr>
  1492. <tr>
  1493. <td>
  1494. <p>
  1495. rayleigh_skewness
  1496. </p>
  1497. </td>
  1498. <td>
  1499. <p>
  1500. 2&#8730;&#960;(&#960;-3)/(4 - &#960;)<sup>3/2</sup>
  1501. </p>
  1502. </td>
  1503. <td>
  1504. <p>
  1505. 0.631110
  1506. </p>
  1507. </td>
  1508. <td>
  1509. <p>
  1510. Rayleigh distribution skewness
  1511. </p>
  1512. </td>
  1513. </tr>
  1514. <tr>
  1515. <td>
  1516. <p>
  1517. rayleigh_kurtosis_excess
  1518. </p>
  1519. </td>
  1520. <td>
  1521. <p>
  1522. -(6&#960;<sup>2</sup>-24&#960;+16)/(4-&#960;)<sup>2</sup>
  1523. </p>
  1524. </td>
  1525. <td>
  1526. <p>
  1527. 0.245089
  1528. </p>
  1529. </td>
  1530. <td>
  1531. <p>
  1532. <a href="http://en.wikipedia.org/wiki/Rayleigh_distribution" target="_top">Rayleigh
  1533. distribution kurtosis excess</a>
  1534. </p>
  1535. </td>
  1536. </tr>
  1537. <tr>
  1538. <td>
  1539. <p>
  1540. rayleigh_kurtosis
  1541. </p>
  1542. </td>
  1543. <td>
  1544. <p>
  1545. 3+(6&#960;<sup>2</sup>-24&#960;+16)/(4-&#960;)<sup>2</sup>
  1546. </p>
  1547. </td>
  1548. <td>
  1549. <p>
  1550. 3.245089
  1551. </p>
  1552. </td>
  1553. <td>
  1554. <p>
  1555. Rayleigh distribution kurtosis
  1556. </p>
  1557. </td>
  1558. </tr>
  1559. </tbody>
  1560. </table></div>
  1561. </div>
  1562. <br class="table-break"><div class="note"><table border="0" summary="Note">
  1563. <tr>
  1564. <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../doc/src/images/note.png"></td>
  1565. <th align="left">Note</th>
  1566. </tr>
  1567. <tr><td align="left" valign="top"><p>
  1568. Integer values are <span class="bold"><strong>not included</strong></span> in this
  1569. list of math constants, however interesting, because they can be so easily
  1570. and exactly constructed, even for UDT, for example: <code class="computeroutput"><span class="keyword">static_cast</span><span class="special">&lt;</span><span class="identifier">cpp_float</span><span class="special">&gt;(</span><span class="number">42</span><span class="special">)</span></code>.
  1571. </p></td></tr>
  1572. </table></div>
  1573. <div class="tip"><table border="0" summary="Tip">
  1574. <tr>
  1575. <td rowspan="2" align="center" valign="top" width="25"><img alt="[Tip]" src="../../../../../doc/src/images/tip.png"></td>
  1576. <th align="left">Tip</th>
  1577. </tr>
  1578. <tr><td align="left" valign="top"><p>
  1579. If you know the approximate value of the constant, you can search for the
  1580. value to find Boost.Math chosen name in this table.
  1581. </p></td></tr>
  1582. </table></div>
  1583. <div class="tip"><table border="0" summary="Tip">
  1584. <tr>
  1585. <td rowspan="2" align="center" valign="top" width="25"><img alt="[Tip]" src="../../../../../doc/src/images/tip.png"></td>
  1586. <th align="left">Tip</th>
  1587. </tr>
  1588. <tr><td align="left" valign="top"><p>
  1589. Bernoulli numbers are available at <a class="link" href="number_series/bernoulli_numbers.html" title="Bernoulli Numbers">Bernoulli
  1590. numbers</a>.
  1591. </p></td></tr>
  1592. </table></div>
  1593. <div class="tip"><table border="0" summary="Tip">
  1594. <tr>
  1595. <td rowspan="2" align="center" valign="top" width="25"><img alt="[Tip]" src="../../../../../doc/src/images/tip.png"></td>
  1596. <th align="left">Tip</th>
  1597. </tr>
  1598. <tr><td align="left" valign="top"><p>
  1599. Factorials are available at <a class="link" href="factorials/sf_factorial.html" title="Factorial">factorial</a>.
  1600. </p></td></tr>
  1601. </table></div>
  1602. </div>
  1603. <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
  1604. <td align="left"></td>
  1605. <td align="right"><div class="copyright-footer">Copyright &#169; 2006-2019 Nikhar
  1606. Agrawal, Anton Bikineev, Paul A. Bristow, Marco Guazzone, Christopher Kormanyos,
  1607. Hubert Holin, Bruno Lalande, John Maddock, Jeremy Murphy, Matthew Pulver, Johan
  1608. R&#229;de, Gautam Sewani, Benjamin Sobotta, Nicholas Thompson, Thijs van den Berg,
  1609. Daryle Walker and Xiaogang Zhang<p>
  1610. Distributed under the Boost Software License, Version 1.0. (See accompanying
  1611. file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
  1612. </p>
  1613. </div></td>
  1614. </tr></table>
  1615. <hr>
  1616. <div class="spirit-nav">
  1617. <a accesskey="p" href="tutorial/user_def.html"><img src="../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../constants.html"><img src="../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="new_const.html"><img src="../../../../../doc/src/images/next.png" alt="Next"></a>
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