sin²x怎样求导

sin²x怎样求导
sin²x怎样求导

sin²x怎样求导
(sinx)^2=(1-cos2x)/2,故：(sinx)^2'=[(1-cos2x)/2]'=(2x)'(-cos2x)'/2=sin2x

(sinx^2)'=(cosx^2)*2x
((sinx)^2)'=2sinx*cosx

f(x)=(sinx)^2
令g(x)=sinx
f(g(x))=g(x)^2
f'(g(x))=2*g(x)
g'(x)=cosx
[f(g(x))]'=f'(g(x))*g'(x)=2*g(x)*g'(x)=2*sinx*cosx=sin2x
望采纳小女子答案为满意答案 谢谢