不難付加maTHS第4回

d(x^n)/dx = nx^n-1
X=t^2
dx/dt=2t
Y=2t
dy/dt=2
當=2,
dy/dx│2
= (dy/dt) / (dx/dt)
= 2/2t
=2/2(2)
=1/2

X=t^2, Y=2t
dx=2t
dy=2
dy/dx =2/2t
當t=2時,
dy/dx
=2/2(2)
=1/2