Chapter 2 - The Derivative - 2.5 Derivatives of Trigonometric Functions - Exercises Set 2.5 - Page 151: 1

$=-4sinx+2cosx$

Use the derivative of $sinx (cosx)$ and the derivative of $cosx (-sinx)$ to differentiate each term. The $4$ and $2$ before the functions are constants, so they are just multiplied to the derivative. Therefore, the derivative is $=-4sinx+2cosx$.