根据三角函数的定义，我们还可以得出
ＳｉｎＡ＊２＋ＣｏｓＡ＊２＝１
ＴａｎＡ · ＣｏｔＡ＝１
ＴａｎＡ＝ＳｉｎＡ／ＣｏｓＡ
ＣｏｔＡ＝ＣｏｓＡ／ＳｉｎＡ
ＴａｎＡ＝１／ＣｏｔＡ
sinA=cos（90-A）
tanA=cotA（90-A）
此为必背图表
角度
三角函数
０度
３０度
４５度
６０度
９０度
ｓｉｎ
０
１／２
１
ｃｏｓ
１
１／２
０
ｔａｎ
０
１
――
ｃｏｔ
――
１
０
相对应的示意图见下页～～～～～～～～～～～～～～～～～
＜Ａ＝３０度
＜Ａ＝４５度
＜Ａ＝６０度
如何用计算器计算函数值
（1） 求已知锐角的三角函数值
求sin63°52′41″的值．（精确到0．0001）
先用如下方法将角度单位状态设定为“度”：
SHIFT MODE（SETUP）３ 显示Ｄ
依次键入 sin 63 ° 52 ′ 41 ″ ＝
得到结果；
求cot70°45′的值．（精确到0．0001）
在角度单位状态为“度”的情况下（屏幕显示），
按下列顺序依次按键：
１ ÷ cot 70 ° 45 ′ ＝
得到结果
（2） 由锐角三角函数值求锐角
已知tanx＝0．7410，求锐角x．（精确到1′）
在角度单位状态为“度”的情况下（屏幕显示），
按下列顺序依次按键：
SHIFT tan （
）0 · ７４１ ＝ ０
得到结果
再次键入 SHIFT o’’’ 完成
接下来如标题示，整理好的三角函数表
sin15=（√6-√2）/4,
sin75=（√6+√2）/2,
sin105=√2/2*（√3/2+1/2）
sin120=√3/2
sin135=√2/2
sin150=1/2
sin165=（√6-√2）/4
sin180=0
sin270=-1
sin360=0
（上为特殊值）
sin1=0.01745
sin2=0.034899
sin3=0.052335
sin4=0.069756
sin5=0.087155
sin6=0.104528
sin7=0.121869
sin8=0.139173
sin9=0.156434
sin10=0.17364
sin11=0.19080
sin12=0.20791
sin13=0.22495
sin14=0.24192
sin15=0.25881
sin16=0.27563
sin17=0.29237
sin18=0.30901
sin19=0.32556
sin20=0.34202
sin21=0.35836
sin22=0.37460
sin23=0.39073
sin24=0.40673
sin25=0.42261
sin26=0.43837
sin27=0.45399
sin28=0.46947
sin29=0.48480
sin30=0.49999
sin31=0.51503
sin32=0.52991
sin33=0.54463
sin34=0.55919
sin35=0.57357
sin36=0.58778
sin37=0.60181
sin38=0.61566
sin39=0.62932
sin40=0.64278
sin41=0.65605
sin42=0.66913
sin43=0.68199
sin44=0.69465
sin45=0.70710
sin46=0.71933
sin47=0.73135
sin48=0.74314
sin49=0.75470
sin50=0.76604
sin51=0.77714
sin52=0.78801
sin53=0.79863
sin54=0.80901
sin55=0.81915
sin56=0.82903
sin57=0.83867
sin58=0.84804
sin59=0.85716
sin60=0.86602
sin61=0.87461
sin62=0.88294
sin63=0.89100
sin64=0.89879
sin65=0.90630
sin66=0.91354
sin67=0.92050
sin68=0.92718
sin69=0.93358
sin70=0.93969
sin71=0.94551
sin72=0.95105
sin73=0.95630
sin74=0.96126
sin75=0.96592
sin76=0.97029
sin77=0.97437
sin78=0.97814
sin79=0.98162
sin80=0.98480
sin81=0.98768
sin82=0.99026
sin83=0.99254
sin84=0.99452
sin85=0.99619
sin86=0.99756
sin87=0.99862
sin88=0.99939
sin89=0.99984
sin90=1
cos1=0.99984
cos2=0.99939
cos3=0.99862
cos4=0.99756
cos5=0.99619
cos6=0.99452
cos7=0.99254
cos8=0.99026
cos9=0.98768
cos10=0.9848
cos11=0.9816
cos12=0.97814
cos13=0.9743
cos14=0.9702
cos15=0.9659
cos16=0.9612
cos17=0.9563
cos18=0.9510
cos19=0.9455
cos20=0.9396
cos21=0.9335
cos22=0.9271
cos23=0.9205
cos24=0.9135
cos25=0.9063
cos26=0.8987
cos27=0.8910
cos28=0.8829
cos29=0.8746
cos30=0.8660
cos31=0.8571
cos32=0.8480
cos33=0.8386
cos34=0.8290
cos35=0.8191
cos36=0.8090
cos37=0.7986
cos38=0.7880
cos39=0.7771
cos40=0.7660
cos41=0.7547
cos42=0.7431
cos43=0.7313
cos44=0.7193
cos45=0.7071
cos46=0.6946
cos47=0.6819
cos48=0.6691
cos49=0.6560
cos50=0.6427
cos51=0.6293
cos52=0.6156
cos53=0.6018
cos54=0.5877
cos55=0.5735
cos56=0.5592
cos57=0.5446
cos58=0.5299
cos59=0.5150
cos60=0.5000
cos61=0.4848
cos62=0.4694
cos63=0.4539
cos64=0.4383
cos65=0.4226
cos66=0.4067
cos67=0.3907
cos68=0.3746
cos69=0.3583
cos70=0.3420
cos71=0.3255
cos72=0.3090
cos73=0.2923
cos74=0.2756
cos75=0.2588
cos76=0.2419
cos77=0.2249
cos78=0.2079
cos79=0.1908
cos80=0.1736
cos81=0.1564
cos82=0.1391
cos83=0.1218
cos84=0.1045
cos85=0.0871
cos86=0.06973
cos87=0.052
cos88=0.0348
cos89=0.0174
cos90=0
tan1=0.017455
tan2=0.034920
tan3=0.052407
tan4=0.069926
tan5=0.087488
tan6=0.105104
tan7=0.122784
tan8=0.140540
tan9=0.158384
tan10=0.17632
tan11=0.19438
tan12=0.21255
tan13=0.23086
tan14=0.24932
tan15=0.26794
tan16=0.28674
tan17=0.30573
tan18=0.32491
tan19=0.34432
tan20=0.36397
tan21=0.38386
tan22=0.40402
tan23=0.42447
tan24=0.44522
tan25=0.46630
tan26=0.48773
an27=0.50952
tan28=0.53170
tan29=0.55430
tan30=0.57735
tan31=0.60086
tan32=0.62486
tan33=0.64940
tan34=0.67450
tan35=0.70020
tan36=0.72654
tan37=0.75355
tan38=0.78128
tan39=0.80978
tan40=0.83909
tan41=0.86928
tan42=0.90040
tan43=0.93251
tan44=0.96568
tan45=0.99999
tan46=1.03553
tan47=1.07236
tan48=1.11061
tan49=1.15036
tan50=1.19175
tan51=1.23489
tan52=1.27994
tan53=1.32704
tan54=1.3763
tan55=1.42814
tan56=1.48256
tan57=1.53986
tan58=1.60033
tan59=1.66427
tan60=1.73205
tan61=1.80404
tan62=1.88072
tan63=1.96261
tan64=2.05030
tan65=2.14450
tan66=2.24603
tan67=2.35585
tan68=2.47508
tan69=2.60508
tan70=2.74747
tan71=2.90421
tan72=3.07768
tan73=3.27085
tan74=3.48741
tan75=3.73205
tan76=4.01078
tan77=4.33147
tan78=4.70463
tan79=5.14455
tan80=5.67128
tan81=6.31375
tan82=7.11536
tan83=8.14434
tan84=9.51436
tan85=11.4300
tan86=14.3006
tan87=19.0811
tan88=28.6362
tan89=57.2899
tan90=无取值
如果求精确度的话，还可以看下面
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=0.0174524064372
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