Question

find the derivative of the following w.r.x cos ( 1-x))​

Answer 1

$\huge\mathbb\color{green}{AN}\purple{SW}\pink{ER}\color{blue}{:}$

$\frac{dy}{dx} = \frac{d \: \: cos(1 - x)}{dx} \\ \: \: \: \: \: \: = - sin(1 - x) \: \frac{d \: \: (1 - x)}{dx} \\ \: \: \: \: \: \: \: = - sin(1 - x) \times ( - 1) \\ \: \: \: \: \: \: \: = sin(1 - x)$

Answer 2

$\frac{dy}{dx} = \frac{d \: cos(1 - x)}{dx}$

$= - sin( 1 - \: x) \frac{d \: \: (1 - x)}{dx} \\ \\ = - sin(1 - x) \times ( - 1) \\ = sin \: (1 - x)$