sin(2x-30度)怎么就变成了cos(2x-60度)?
化简:1+sin(x-360度)cos(x-270度)-2cos平方x
若f(cos x)=cos 2x,则f(sin 15度)的值?
(sin^2x+cos^2x )(sin^2x-cos^2x)怎么得sin^2x-cos^2x?
Y=sin(x+15度)+根号2cos(x+60度)最大值
已知cos(x-45度)=十分之根号二,X属于(90度,135度).求sin x的值、sin(2x+60度)的值
证明COS(X+Y)COS(X-Y)=COS^2X-SIN^2Y
为什么-sin2x+cos2x=√2cos(2x+兀/4),辅助角公式不是sin嘛 怎么变成cos了
sin(sin(sin(sin(x)=cos(cos(cos(cos(x),X等于多少?
化简(1)√3sin x+cos x (2)√2(sin x-cos x) (3)√2cos x-√6sin x
化简sin(2π+x)cos(π-x)sin(π-x)/cos(x-π)sin(-π-x)sin(π+x)
lim(sin(x^2*cos(1/x)))/x怎么做?
cos(2x+派/2)=sin(2x)?