三角函数概念的发生与发展，经历了一个很长的时期.从历史上看，三角学是伴随着测量与天文学的研究而产生的，为了测量就要解三角形，而每一个三角形都可以分为两个直
角三角形，所以如何解三角形的问题就更本质地变为如何解直角三角形的问题.虽然远在公元前人们就知道了直角三角形中角与角和边与边之间的关系，即A+B=90°和a的平方+b的平方=c的平方,但由此还解决不了解直角三角形的问题.例如已知直角三角形的一个锐角和任意一条边的长度，或已知任意两条边的长度,都能唯一地确定这个三角形，但是如果不通过作图和度量，纯粹用计算的方法是无法求出其他元素的值的.为了解决这一问题，促使人们考虑，必须建立直角三角形中边与角之间的联系.人们从相似三角形的原理发现，不论直角三角形的大小如何，它的任意一个锐角都可由任总两边的比值来确定.
因此，如果把各个不同锐角的直角三角形的某两边之比的比值预先算出来，就可以利用它来解直角三角形了.在古希暗时代的天文学家托勒密（约公元85—165年）的著作中，就已出现了在固定的圆中，从0°到180°每隔半度的圆心角所对的弦长表，以今天的观点来看，也就是从0°到90°每隔四分之一度的正弦表.这一弦长表的产生，对解三角形来说犹如“绝处逢生”，开拓了一条广阔的新路.同时它也孕育了锐角三角函数的概念.其后，经历了一个较长的历史时期，经过许多人的勤奋研究，制作了大量的三角函数表。
18世纪的伟大数学家欧拉首先提出了用圆中某些线段与半径之比来定义三角函数，这不但为我们今天所采用的三角函数的坐标定义奠定了基础，而且使三角学从只是研究三角形的解法中解脱出来，为三角函数的理论研究和应用开拓了广阔的天地.
在三角函数的定义中，自变量与函数间的对应关系，原是通过几何方法建立起来的，但随着近代分析数学的发展，三角学的解析理论也得到发展，现在已完全可以不依赖于几何意义的陈述，而用解析的方法来直接定义三角函数。
三角函数表值查表大全
| 正弦函数 sin（A）=a/h |
| 余弦函数 cos（A）=b/h |
| 正切函数 tan（A）=a/b |
| 余切函数 cot（A）=b/a |
| 正割函数 sec (A) =h/b |
| 余割函数 csc (A) =h/a |
| 注：a—所研究角的对边 |
| b—所研究的邻边 |
| h—所研究角的斜边 |
| 以下是三角函数表值具体的对应参数表： |
| 1，正弦函数表 sin |
| sin1=0.01745240643728351 sin2=0.03489949670250097 sin3=0.05233595624294383 |
| sin4=0.0697564737441253 sin5=0.08715574274765816 sin6=0.10452846326765346 |
| sin7=0.12186934340514747 sin8=0.13917310096006544 sin9=0.15643446504023087 |
| sin10=0.17364817766693033 sin11=0.1908089953765448 sin12=0.20791169081775931 |
| sin13=0.22495105434386497 sin14=0.24192189559966773 sin15=0.25881904510252074 |
| sin16=0.27563735581699916 sin17=0.2923717047227367 sin18=0.3090169943749474 |
| sin19=0.3255681544571567 sin20=0.3420201433256687 sin21=0.35836794954530027 |
| sin22=0.374606593415912 sin23=0.3907311284892737 sin24=0.40673664307580015 |
| sin25=0.42261826174069944 sin26=0.4383711467890774 sin27=0.45399049973954675 |
| sin28=0.4694715627858908 sin29=0.48480962024633706 sin30=0.49999999999999994 |
| sin31=0.5150380749100542 sin32=0.5299192642332049 sin33=0.544639035015027 |
| sin34=0.5591929034707468 sin35=0.573576436351046 sin36=0.5877852522924731 |
| sin37=0.6018150231520483 sin38=0.6156614753256583 sin39=0.6293203910498375 |
| sin40=0.6427876096865392 sin41=0.6560590289905073 sin42=0.6691306063588582 |
| sin43=0.6819983600624985 sin44=0.6946583704589972 sin45=0.7071067811865475 |
| sin46=0.7193398003386511 sin47=0.7313537016191705 sin48=0.7431448254773941 |
| sin49=0.7547095802227719 sin50=0.766044443118978 sin51=0.7771459614569708 |
| sin52=0.7880107536067219 sin53=0.7986355100472928 sin54=0.8090169943749474 |
| sin55=0.8191520442889918 sin56=0.8290375725550417 sin57=0.8386705679454239 |
| sin58=0.848048096156426 sin59=0.8571673007021122 sin60=0.8660254037844386 |
| sin61=0.8746197071393957 sin62=0.8829475928589269 sin63=0.8910065241883678 |
| sin64=0.898794046299167 sin65=0.9063077870366499 sin66=0.9135454576426009 |
| sin67=0.9205048534524404 sin68=0.9271838545667873 sin69=0.9335804264972017 |
| sin70=0.9396926207859083 sin71=0.9455185755993167 sin72=0.9510565162951535 |
| sin73=0.9563047559630354 sin74=0.9612616959383189 sin75=0.9659258262890683 |
| sin76=0.9702957262759965 sin77=0.9743700647852352 sin78=0.9781476007338057 |
| sin79=0.981627183447664 sin80=0.984807753012208 sin81=0.9876883405951378 |
| sin82=0.9902680687415704 sin83=0.992546151641322 sin84=0.9945218953682733 |
| sin85=0.9961946980917455 sin86=0.9975640502598242 sin87=0.9986295347545738 |
| sin88=0.9993908270190958 sin89=0.9998476951563913 |
| sin90=1 |
| 2，余弦函数表 cos |
| cos1=0.9998476951563913 cos2=0.9993908270190958 cos3=0.9986295347545738 |
| cos4=0.9975640502598242 cos5=0.9961946980917455 cos6=0.9945218953682733 |
| cos7=0.992546151641322 cos8=0.9902680687415704 cos9=0.9876883405951378 |
| cos10=0.984807753012208 cos11=0.981627183447664 cos12=0.9781476007338057 |
| cos13=0.9743700647852352 cos14=0.9702957262759965 cos15=0.9659258262890683 |
| cos16=0.9612616959383189 cos17=0.9563047559630355 cos18=0.9510565162951535 |
| cos19=0.9455185755993168 cos20=0.9396926207859084 cos21=0.9335804264972017 |
| cos22=0.9271838545667874 cos23=0.9205048534524404 cos24=0.9135454576426009 |
| cos25=0.9063077870366499 cos26=0.898794046299167 cos27=0.8910065241883679 |
| cos28=0.882947592858927 cos29=0.8746197071393957 cos30=0.8660254037844387 |
| cos31=0.8571673007021123 cos32=0.848048096156426 cos33=0.838670567945424 |
| cos34=0.8290375725550417 cos35=0.8191520442889918 cos36=0.8090169943749474 |
| cos37=0.7986355100472928 cos38=0.7880107536067219 cos39=0.7771459614569709 |
| cos40=0.766044443118978 cos41=0.754709580222772 cos42=0.7431448254773942 |
| cos43=0.7313537016191705 cos44=0.7193398003386512 cos45=0.7071067811865476 |
| cos46=0.6946583704589974 cos47=0.6819983600624985 cos48=0.6691306063588582 |
| cos49=0.6560590289905074 cos50=0.6427876096865394 cos51=0.6293203910498375 |
| cos52=0.6156614753256583 cos53=0.6018150231520484 cos54=0.5877852522924731 |
| cos55=0.5735764363510462 cos56=0.5591929034707468 cos57=0.5446390350150272 |
| cos58=0.5299192642332049 cos59=0.5150380749100544 cos60=0.5000000000000001 |
| cos61=0.4848096202463371 cos62=0.46947156278589086 cos63=0.4539904997395468 |
| cos64=0.43837114678907746 cos65=0.42261826174069944 cos66=0.4067366430758004 |
| cos67=0.3907311284892737 cos68=0.3746065934159122 cos69=0.35836794954530015 |
| cos70=0.3420201433256688 cos71=0.32556815445715675 cos72=0.30901699437494745 |
| cos73=0.29237170472273677 cos74=0.27563735581699916 cos75=0.25881904510252074 |
| cos76=0.24192189559966767 cos77=0.22495105434386514 cos78=0.20791169081775923 |
| cos79=0.19080899537654491 cos80=0.17364817766693041 cos81=0.15643446504023092 |
| cos82=0.13917310096006546 cos83=0.12186934340514749 cos84=0.10452846326765346 |
| cos85=0.08715574274765836 cos86=0.06975647374412523 cos87=0.052335956242943966 |
| cos88=0.03489949670250108 cos89=0.0174524064372836 |
| cos90=0 |
| 3，正切函数表 tan |
| tan1=0.017455064928217585 tan2=0.03492076949174773 tan3=0.052407779283041196 |
| tan4=0.06992681194351041 tan5=0.08748866352592401 tan6=0.10510423526567646 |
| tan7=0.1227845609029046 tan8=0.14054083470239145 tan9=0.15838444032453627 |
| tan10=0.17632698070846497 tan11=0.19438030913771848 tan12=0.2125565616700221 |
| tan13=0.2308681911255631 tan14=0.24932800284318068 tan15=0.2679491924311227 |
| tan16=0.2867453857588079 tan17=0.30573068145866033 tan18=0.3249196962329063 |
| tan19=0.34432761328966527 tan20=0.36397023426620234 tan21=0.3838640350354158 |
| tan22=0.4040262258351568 tan23=0.4244748162096047 tan24=0.4452286853085361 |
| tan25=0.4663076581549986 tan26=0.4877325885658614 tan27=0.5095254494944288 |
| tan28=0.5317094316614788 tan29=0.554309051452769 tan30=0.5773502691896257 |
| tan31=0.6008606190275604 tan32=0.6248693519093275 tan33=0.6494075931975104 |
| tan34=0.6745085168424265 tan35=0.7002075382097097 tan36=0.7265425280053609 |
| tan37=0.7535540501027942 tan38=0.7812856265067174 tan39=0.8097840331950072 |
| tan40=0.8390996311772799 tan41=0.8692867378162267 tan42=0.9004040442978399 |
| tan43=0.9325150861376618 tan44=0.9656887748070739 tan45=0.9999999999999999 |
| tan46=1.0355303137905693 tan47=1.0723687100246826 tan48=1.1106125148291927 |
| tan49=1.1503684072210092 tan50=1.19175359259421 tan51=1.234897156535051 |
| tan52=1.2799416321930785 tan53=1.3270448216204098 tan54=1.3763819204711733 |
| tan55=1.4281480067421144 tan56=1.4825609685127403 tan57=1.5398649638145827 |
| tan58=1.6003345290410506 tan59=1.6642794823505173 tan60=1.7320508075688767 |
| tan61=1.8040477552714235 tan62=1.8807264653463318 tan63=1.9626105055051503 |
| tan64=2.050303841579296 tan65=2.1445069205095586 tan66=2.246036773904215 |
| tan67=2.355852365823753 tan68=2.4750868534162946 tan69=2.6050890646938023 |
| tan70=2.7474774194546216 tan71=2.904210877675822 tan72=3.0776835371752526 |
| tan73=3.2708526184841404 tan74=3.4874144438409087 tan75=3.7320508075688776 |
| tan76=4.0107809335358455 tan77=4.331475874284153 tan78=4.704630109478456 |
| tan79=5.144554015970307 tan80=5.671281819617707 tan81=6.313751514675041 |
| tan82=7.115369722384207 tan83=8.144346427974593 tan84=9.514364454222587 |
| tan85=11.43005230276132 tan86=14.300666256711942 tan87=19.08113668772816 |
| tan88=28.636253282915515 tan89=57.289961630759144 |
| tan90=(无限) |
| 4，余切函数 cot |
| cot89=0.017455064928217585 cot88=0.03492076949174773 cot87=0.052407779283041196 |
| cot86=0.06992681194351041 cot85=0.08748866352592401 cot84=0.10510423526567646 |
| cot83=0.1227845609029046 cot83=0.14054083470239145 cot81=0.15838444032453627 |
| cot80=0.17632698070846497 cot79=0.19438030913771848 cot78=0.2125565616700221 |
| cot77=0.2308681911255631 cot76=0.24932800284318068 cot75=0.2679491924311227 |
| cot74=0.2867453857588079 cot73=0.30573068145866033 cot72=0.3249196962329063 |
| cot71=0.34432761328966527 cot70=0.36397023426620234 cot69=0.3838640350354158 |
| cot68=0.4040262258351568 cot67=0.4244748162096047 cot66=0.4452286853085361 |
| cot65=0.4663076581549986 cot64=0.4877325885658614 cot63=0.5095254494944288 |
| cot62=0.5317094316614788 cot61=0.554309051452769 cot60=0.5773502691896257 |
| cot59=0.6008606190275604 cot58=0.6248693519093275 cot57=0.6494075931975104 |
| cot56=0.6745085168424265 cot55=0.7002075382097097 cot54=0.7265425280053609 |
| cot53=0.7535540501027942 cot52=0.7812856265067174 cot51=0.8097840331950072 |
| cot50=0.8390996311772799 cot49=0.8692867378162267 cot48=0.9004040442978399 |
| cot47=0.9325150861376618 cot46=0.9656887748070739 cot45=0.9999999999999999 |
| cot44=1.0355303137905693 cot43=1.0723687100246826 cot42=1.1106125148291927 |
| cot41=1.1503684072210092 cot40=1.19175359259421 cot39=1.234897156535051 |
| cot38=1.2799416321930785 cot37=1.3270448216204098 cot36=1.3763819204711733 |
| cot35=1.4281480067421144 cot34=1.4825609685127403 cot33=1.5398649638145827 |
| cot32=1.6003345290410506 cot31=1.6642794823505173 cot30=1.7320508075688767 |
| cot29=1.8040477552714235 cot28=1.8807264653463318 cot27=1.9626105055051503 |
| cot26=2.050303841579296 cot25=2.1445069205095586 cot24=2.246036773904215 |
| cot23=2.355852365823753 cot22=2.4750868534162946 cot21=2.6050890646938023 |
| cot20=2.7474774194546216 cot19=2.904210877675822 cot18=3.0776835371752526 |
| cot17=3.2708526184841404 cot16=3.4874144438409087 cot15=3.7320508075688776 |
| cot14=4.0107809335358455 cot13=4.331475874284153 cot12=4.704630109478456 |
| cot11=5.144554015970307 cot10=5.671281819617707 cot9=6.313751514675041 |
| cot8=7.115369722384207 cot7=8.144346427974593 cot6=9.514364454222587 |
| cot5=11.43005230276132 cot4=14.300666256711942 cot3=19.08113668772816 |
| cot228.636253282915515 cot1=57.289961630759144 |
| cot0=(无限) |