由y=t³+2t得：dy/dt=3t^2+2由x- eˆx sint +1=0得：1-(e^xsint+e^xcostdt/dx)=0得：dt/dx=(1-e^xsint)/e^xcostdy/dx=(dy/dt)*(dt/dx) =(3t^2+2)*(1-e^xsint)/e^xcost