If x=cost(3 - 2 cos^2t) and y= sint(3 - 2 sin^2t) find dy/dx at t = pi / 4 Share with your friends Share 22 Prasanta answered this x=cos t3-2cos2t⇒x=3cos t-2cos3t ⇒dxdt=-3sin t - 6cos2t-sin t ⇒dxdt=-3sin t + 6sin t1-sin2t ⇒dxdt=-3sin t + 6sin t-6sin3t ⇒dxdt=-6sin3t+3sin t ------------(1) Also, y=sin t3-2sin2t⇒y=3sin t-2sin3t ⇒dydt=3cos t-6sin2tcos t ⇒dydt=3cos t-6cos t1-cos2t ⇒dydt=3cos t-6cos t+6cos3t ⇒dydt=6cos3t-3cos t -------------(2) (2)÷(1)⇒dydx=6cos3t-3cos t-6sin3t+3sint ⇒dydx=2cos3t-cos t-2sin3t+sint ⇒dydx=cot t1-2sin2t-1+2cos2t ∴dydx at t=π4=cotπ41-2sin2π4-1+2cos2π4 =11-2122-1+2122 =00 =undefined 1 View Full Answer Tarun Garg answered this undefined -10