看 y=arctanx,则x=tany arctanx′=1/tany′ tany′=(siny/cosy)′=cosycosy-siny(-siny)/cos²y=1/cos²y 则arctanx′=cos²y=cos²y/sin²y+cos²y=1/1+tan²y=1/1+x²
x=tany
y= arctanx
dx/dy =1/sec^2(y)=1/(1+tan^2(y))=1/(1+x^2)
y'(x)=1/1+x^2
扩展资料:
三角函数求导公式:
(arcsinx)'=1/(1-x^2)^1/2
(arccosx)'=-1/(1-x^2)^1/2
(arctanx)'=1/(1+x^2)
(arccotx)'=-1/(1+x^2)
(arcsecx)'=1/(|x|(x^2-1)^1/2)
(arccscx)'=-1/(|x|(x^2-1)^1/2)
(arctanx)'=1/(1+x^2)
1/(1+x²)+C