解:这其实是一个复合函数求导问题。y=arctanu,u=1-x².y'(x)=y'(u)×u'(x)=[1/(1+u²)]×(-2x)=(-2x)/(x^4-2x²+2).∴y'=(-2x)/(x^4-2x²+2).
y的倒数为其反函数的tan(1-x^2)倒数
y'=1/tan(1-x^2)'
复合函数求导
tan(1-x^2)'=(sec(1-x^2))^2(1-x^2)'
=(sec(1-x^2))^2(-2x)
y'=1/(sec(1-x^2))^2(-2x)
=-1/-2x(sec(1-x^2))^2
好久没算了,不知道公式记得准不准了
(arctan(1-x^2))'=1/(1+(1-x²)²)(1-x²)’
=(-2x)/(1+(1-x²)²)
=-2x/(x^4-2x²+2)