# How do you find the derivative of f(x) = (5x^2 + 11)e^(-21x)?

May 17, 2018

$f ' \left(x\right) = - 21 \cdot \left(5 {x}^{2} + 11\right) \cdot {e}^{- 21 x} + \left(10 x\right) \cdot {e}^{- 21 x}$

#### Explanation:

show below

$f \left(x\right) = \left(5 {x}^{2} + 11\right) \cdot {e}^{- 21 x}$

$f ' \left(x\right) = \left(5 {x}^{2} + 11\right) \cdot - 21 \cdot {e}^{- 21 x} + {e}^{- 21 x} \cdot \left(10 x\right)$

$f ' \left(x\right) = - 21 \cdot \left(5 {x}^{2} + 11\right) \cdot {e}^{- 21 x} + \left(10 x\right) \cdot {e}^{- 21 x}$