函数的求导法则y=(x^2-5)^3+2(x^2-5)^2怎么求?

问题描述:

函数的求导法则
y=(x^2-5)^3+2(x^2-5)^2怎么求?

设x^2-5=t,则y=t^3+2t^2
则y'=3t^2*t'+4t*t'
=3(x^2-5)^2*2x+4x*2x
=6x^2-30+8x^2
=14x^2-30

y的导数:
=[3(x^2-5)^2]*2x+2*[2(x^2-5)]*2x
(说明:先求外层幂函数的导数,再乘以内层x^2-5的导数2x,建议多看看复合函数求导的规则,多练习就很容易掌握)
=2x(x^2-5)(3x^2-11)