If x = 3 tant and y = 3 sec t, then the value of `(d^2y)/(dx^2)" at" t=pi/4` is

If x = 3 tan t and y = 3 sec t then the value of (d^2y)/(dx^2) at t = pi/4 , is 1/(ksqrt2) . The value of k is _________.

If x=a(cost+tsint) and y=a(sint-tcost), then find the value of (d^2y)/(dx^2) at t=pi/4

IF y=(cost)^5 and x=sint then the value of 2((d^2y)/(dx^2)) at t=(2pi)/9 is-

If x=2 cos t+cos 2t and y=2 sin t-sin2t , then the value of (dy)/(dx) at t=(pi)/(4) is -

If x sec theta , y = tan theta , then the value of (d^(2) y)/(dx^(2)) " at " theta = (pi)/(4) is

If x= cos t+ log tan t/2 and y = sin t, then find the value of (d^2y)/(dt^2) and (d^2y)/(dx^2) at t= (pi)/4 .

If x = 2 cos t - cos 2t , y = 2 sin t - sin 2t , then the value of d^2y/dx^2 at t=pi//2 is