Question

Second derivative of Y=cos^3x then Y''=

Answer 1

y=
$y = \cos( {3x}^{} ) \\ \frac{dy}{dx} = - \sin(3x) .3 = - 3 \sin(3x) \\ {d}^{2} \frac{x}{d {y}^{2} } = - 3 \cos(3x)$
-3cos(3x) answer hoga