Find the derivative of d^2Y/dx^2 of y=e^2t and x=cost^2 and leave your answer in terms of x and y

Answer 1

is that (cos t)^2 or cos(t^2) ?

Then express t as functions of x and y, and you have

dy/dx = (dt/dx) / (dt/dy)

then you can use that to get the 2nd derivative