f(x)=tanx的导函数怎么求?
问题描述:
f(x)=tanx的导函数怎么求?
答
解f'(x)=(tanx)'
=(sinx/cosx)'
=[(sinx)'cosx-sinx(cosx)']/cos^2x
=[cosxcosx-sinx(-sinx)]/cos^2x
=[cos^2x+sin^2x]/cos^2x
=1/cos^2x