设参数方程{ x=arctant y=t-ln(1+t^2),则dy/dx=

设参数方程{ x=arctant y=t-ln(1+t^2),则dy/dx=
设参数方程{ x=arctant y=t-ln(1+t^2),则dy/dx=

设参数方程{ x=arctant y=t-ln(1+t^2),则dy/dx=
dy/dx=（dy/dt）/(dx/dt)
dy/dt=1-[2t/(1+t^2)]
dx/dt=1/(1+t^2)
故dy/dx=(t-1)^2