首先记住公式[f(g(x))]'=f'(g(x))*g'(x)然后设a=(1+x^2）/（1-x^2),y=f(a)y=f(a)=a^2f'(a)=2a=2(1+x^2）/（1-x^2)然后设b=1-x^2,a=g(b)a=g(b)=(2-b)/b=2/b-1g'(b)=-2/b^2=-2/(1-x^2)^2b'=-2xa'=[g(b)]'=g'(b)*b'=[-2...