if y = cot x , find d^2 y/ dx^2, at x = pi/4 Share with your friends Share 2 Manbar Singh answered this y = cot x⇒dydx = - cosec2x⇒d2ydx2 = - 2 cosec x . - cot x . cosec x = 2 cot x . cosec2x⇒d2ydx2x=π4 = 2 cotπ4 . cosec2π4 = 2 × 1 × 2 = 4 -6 View Full Answer