化简sin(α 180度)cos(-α)sin(-α-180度)
来源:学生作业帮助网 编辑:作业帮 时间:2024/05/29 18:57:52
cos(540°-α)sin(α-360°)/[sin(-α+180°)cos(180°+α)]=cos(180°-α)[-sin(360°-α)]/[sin(180°-α)cos(180°+α)]=
(1)原式=sinα^2+cosα^2-2sinαcosα=1-sin2α(2)原式=1/2sinθ
sinacosacos2a=1/2sin2acos2a=1/4sin4a再问:最后一步怎么得出来的啊??再答:=1/4(2sin2acos2a)=1/4sin(2x2a)=1/4sin4a
是相乘还是分开的化简我教你方法吧,全部解决就是令a为锐角30°,然后看括号里的度数在第几象限.例如sin(α+180度),a=30a+180在第三象限,那么sin在第三象限为负.所以全部可以出来,
cosαsecα=1sinα/cosα=tanα=secα/cscαcosα/sinα=cotα=cscα/secαsin2α+cos2α=1sin(π/2-α)=cosαsin(π/2+α)=cos
再答:接下去我也不知道是什么问题不能用辅助公式。。。再答:
[cos(a+15度)]^2+[sin(a-15度)]^2+[sin(a+180度)]*[cos(a-180度)]=[cos(2a+30)+1]/2+[1-cos(2a-30)]/2+1/2sin2a
是tanα(cosα-sinα)+[sinα(sinα+tanα)/(1+cosα)]吧?先看sinα(sinα+tanα)/(1+cosα),分子为sinα(sinαcosα/cosα+sinα/c
sin(a+180度)cos(-a)sin(-a-180度)=(-sina)cosasina=-(sina)^2cosa
(1)sin(a+180)cos(-a)sin(-a-180)=(-sina)cosa(-sin(a+180))=sin²acosa.(2)sin³(-a)cos(2π+a)=(-
[cos(a+15度)]^2+[sin(a-15度)]^2+[sin(a+180度)]*[cos(a-180度)]=[cos(2a+30)+1]/2+[1-cos(2a-30)]/2+1/2sin2a
=-sinacosasina=-(sina)^2cosa
sin(α+180°)cos(-α)sin(-α-180°)=-sin(α)cos(α)sin(α)=-2sin(α)sin(2α)
sin2α=2sinαcosαsin2α/sinα-cosα=2sinαcosα/sinα-cosα=2cosα-cosα=cosα
(sinα+cosα)^2=(sinα)^2+(cosα)^2+2sinαcosα=1+2sinαcosα=1+sin2α
cos^2(a+15)+sin^2(a-15)+sin(a+180)cos(a-180)=cos^2(a+15)+sin^2(a-15)+sinacosa=[cos2(a+15)+1]/2+[1-co
sinα的平方+cosα=1-cosα的平方+cosα
(sin²αtanα+cos²α/tanα+2sinαcosα)sinαcosα=(sinα)^4+(cosα)^4+2sin²αcos²α=(sin²
切化弦tanα(cosα-sinα)+sinα(sinα+tanα)/1+cosα.=sinα(cosα-sinα)/cosα+sinα(sinα+sinα/cosα)/(1+cosα)=sinα(c
cos2α=(cosα)^2-(sinα)^2=(cosα+sinα)(cosα-sinα)故答案为cosα