词条 | 三角函数值 |
释义 | 三角函数是数学中属于初等函数中的超越函数的一类函数。它们的本质是任意角的集合与一个比值的集合的变量之间的映射。通常的三角函数是在平面直角坐标系中定义的,其定义域为整个实数域。另一种定义是在直角三角形中,但并不完全。现代数学把它们描述成无穷数列的极限和微分方程的解,将其定义扩展到复数系。 由于三角函数的周期性,它并不具有单值函数意义上的反函数。 数学方程式(数关系 商数关系 tanα=sinα/cosα cotα=cosα/sinα 平方关系 积化合差公式 和差化积公式 三倍角公式 正弦二倍角公式: 余弦二倍角公式: 正切二倍角公式: 降幂公式:) 应用三角函数在复数中有较为重要的应用。在物理学中,三角函数也是常用的工具。 它有六种基本函数: 函数名 正弦 余弦 正切 余切 正割 余割 符号 sin cos tan cot sec csc 正弦函数 sin(A)=a/c 余弦函数 cos(A)=b/c 正切函数 tan(A)=a/b 余切函数 cot(A)=b/a 其中a为对边,b为邻边,c为斜边 三角函数值表sin0=sin0°=0 cos0=cos0°=1 tan0=tan0°=0 sin15=0.65028784015711686582974027098887;sin15°=(√6-√2)/4 cos15=-0.75968791285882127384814640363328;cos15°=(√6+√2)/4 tan15=-0.85599340090851876402619277823803;tan15°=2-√3 sin30=-0.98803162409286178998774890729446;sin30°=1/2 cos30=0.15425144988758405071866214661421;cos30°=√3/2 tan30=-6.405331196646275784896075505668;tan30°=√3/3 sin45=0.85090352453411842486237967761804;sin45°=√2/2 cos45=0.52532198881772969604746440482356;cos45°=sin45°=√2/2 tan45=1.6197751905438615499827965173949;tan45°=1 sin60=-0.30481062110221670562564946547843;sin60°=√3/2 cos60=-0.95241298041515629269381659599293;cos60°=1/2 tan60=0.32004038937956297493818761970571;tan60°=√3 sin75=-0.38778163540943043773094219282288;sin75°=cos15° cos75=0.92175126972474931639229684521414;cos75°=sin15° tan75=-0.42070095062112435384419621180484;tan75°=sin75°/cos75° =2+√3 sin90=0.89399666360055789051826949840421;sin90°=cos0°=1 cos90=-0.44807361612917015236547731439964;cos90°=sin0°=0 tan90=-1.9952004122082420252873530763796;tan90°不存在 sin105=-0.9705352835374847209338032056452;sin105°=cos15° cos105=-0.24095904923620141814219566395281;cos105°=-sin15° tan105=4.0278017638844193492341772197301;tan105°=-cot15° sin120=0.58061118421231428928240695979069;sin120°=cos30° cos120=0.81418097052656176790578986177889;cos120°=-sin30° tan120=0.71312300978590911614556745464875;tan120°=-tan60° sin135=0.088368686104001433036970666416798;sin135°=sin45° cos135=-0.99608783514118495835764440142782;cos135°=-cos45° tan135=-0.088715756770060446136984268003075;tan135°=-tan45° sin150=-0.71487642962916463143638609739663;sin150°=sin30° cos150=0.69925080647837513141645161882553;cos150°=-cos30° tan150=-1.0223462354365875649863661852619;tan150°=-tan30° sin165=0.99779727944989076515961268295525;sin165°=sin15° cos165=-0.066336936335623731837538732255201;cos165°=-cos15° tan165=-15.041353046538895371867886988769;tan165°=-tan15° sin180=-0.80115263573383047774673111582099;sin180°=sin0°=0 cos180=-0.5984600690578581389679486481597;cos180°=-cos0°=-1 tan180=1.3386902103511543616808987449579;tan180°=0 sin195=0.21945466799406361597859718309894;sin195°=-sin15° cos195=0.97562269791944432311811100484535;cos195°=-cos15° tan195=0.22493805080802215296340937063051;tan195°=tan15° sin360=0.95891572341430650775887594775378;sin360°=sin0°=0 cos360=-0.28369109148652733463742432444589;cos360°=cos0°=1 tan360=-3.3801404139609579824775356112668;tan360°=tan0°=0 cos72=[(√5)-1]/4(利用黄金等腰三角形可得出) 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 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 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=无取值 数学方程式数关系tanα ·cotα=1 sinα ·cscα=1 cosα ·secα=1 商数关系tanα=sinα/cosα cotα=cosα/sinα平方关系sinα²+cosα²=1 1+tanα²=secα² 1+cotα²=cscα² 以下关系,函数名不变,图像看象限. sin(2kπ+α)=sinα cos(2kπ+α)=cosα tan(2kπ+α)=tanα cot(2kπ+α)=cotα sin(π+α)=-sinα cos(π+α)=-cosα tan(π+α)=tanα cot(π+α)=cotα sin(π-α)=sinα cos(π-α)=-cosα tan(π-α)=-tanα cot(π-α)=-cotα sin(2π-α)=-sinα cos(2π-α)=cosα tan(2π-α)=-tanα cot(2π-α)=-cotα 以下关系,奇变偶不变,符号看象限 sin(90°-α)=cosα cos(90°-α)=sinα tan(90°-α)=cotα cot(90°-α)=tanα sin(90°+α)=cosα cos(90°+α)=-sinα tan(90°+α)=-cotα cot(90°+α)=-tanα sin(270°-α)=-cosα cos(270°-α)=-sinα tan(270°-α)=cotα cot(270°-α)=tanα sin(270°+α)=-cosα cos(270°+α)=sinα tan(270°+α)=-cotα cot(270°+α)=-tanα 积化合差公式sinα ·cosβ=(1/2)*[sin(α+β)+sin(α-β)] cosα ·sinβ=(1/2)*[sin(α+β)-sin(α-β)] cosα ·cosβ=(1/2)*[cos(α+β)+cos(α-β)] sinα ·sinβ=-(1/2)*[cos(α+β)-cos(α-β)] 和差化积公式sin α+sinβ=2sin[(α+β)/2]·cos[(α-β)/2] sin α-sin β=2cos[(α+β)/2]·sin[(α-β)/2] cos α+cos β=2cos[(α+β)/2]·cos[(α-β)/2] cos α-cos β=-2sin[(α+β)/2]·sin[(α-β)/2] 三倍角公式sin3α=3sinα-4sinα³ cos3α=4cosα³-3cosα 两角和与差的三角函数关系 sin(α+β)=sinαcosβ+cosαsinβ sin(α-β)=sinαcosβ-cosαsinβ cos(α+β)=cosαcosβ-sinαsinβ cos(α-β)=cosαcosβ+sinαsinβ tan(α+β)=(tanα+tanβ )/(1-tanα ·tanβ) tan(α-β)=(tanα-tanβ )/(1+tanα ·tanβ) 正弦二倍角公式:sin2α = 2cosαsinα 推导:sin2A=sin(A+A)=sinAcosA+cosAsinA=2sinAcosA 拓展公式:sin2A=2sinAcosA=2tanAcos^2A=2tanA/[1+tan^2A] 1+sin2A=(sinA+cosA)^2 余弦二倍角公式:余弦二倍角公式有三组表示形式,三组形式等价: 1.Cos2a=Cos^2a-Sin^2a=[1-tan^2a]/[1+tan^2a] 2.Cos2a=1-2Sin^2a 3.Cos2a=2Cos^2a-1 推导:cos2A=cos(A+A)=cosAcosA-sinAsinA=cos^2A-sin^2A=2cos^2A-1 =1-2sin^2A 正切二倍角公式:tan2α=2tanα/[1-tan^2α] 推导:tan2A=tan(A+A)=(tanA+tanA)/(1-tanAtanA)=2tanA/[1-tan^2A] 降幂公式:cosA^2=[1+cos2A]/2 sinA^2=[1-cos2A]/2 tanA^2=[1-cos2A]/[1+cos2A] 变式: sin2α=sin^2(α+π/4)-cos^2(α+π/4)=2sin^2(a+π/4)-1=1-2cos^2(α+π/4); cos2α=2sin(α+π/4)cos(α+π/4) 余弦定理: a^2=b^2+c^2-2bc cosA b^2=c^2+a^2-2ca cosB c^2=a^2+b^2-2ab cosC |
随便看 |
|
百科全书收录4421916条中文百科知识,基本涵盖了大多数领域的百科知识,是一部内容开放、自由的电子版百科全书。