Question

If y=cos^2 x
then find the value of 2nd order derivative of y ....​

Answer 1

Answer:

- 2 cos2x

Step-by-step explanation:

$y = ( cos x)^2\\\frac{dy}{dx} = 2 (cosx) (-sinx)\\\frac{d^2y}{dx^2} = 2 [ cosx (-cos) + (-sinx) (-sinx)]\\                            = 2 [ - cos^2x+sin^2x]\\                            = - 2 [ cos^2x- sin^2x]\\                            =-2cos2x$