If #x=sint# and #y=cost#, then #(d^2y)/dx^2# = ?

1 Answer
Dec 17, 2017

The answer is #=-sec^3t#

Explanation:

#x=sint#

#y=cost#

First calculate the first derivative

#dx/dt=cost#

#dy/dt=-sint#

#dy/dx=-sint/cost=-tant#

To find second derivative

#(d^2y)/dx^2=(d/dt(dy/dx))/(dx/dt)=(-sec^2t)/(cost)#

#=-sec^3t#