解：dy=(x^3)‘cos(x^3)dx=3x^2cos(x^3)dx，d(x^2)=2xdx，则dy/d(x^2)=3x^2cos(x^3)dx/2xdx=3xcos(x^3)/2.
x^2=u, x=u^(1/2)y=sin[u^(3/2)]dy/d(x^2)=dy/du=cos[u^(3/2)] 3/2 u^(1/2)
