What is the derivative of e^(-x^2)?

${f}^{'} \left(x\right) = - 2 x {e}^{- {x}^{2}}$
$f \left(x\right) = {e}^{- {x}^{2}}$
${f}^{'} \left(x\right) = {e}^{- {x}^{2}} . \left(- 2 x\right)$ (chain rule)
${f}^{'} \left(x\right) = - 2 x {e}^{- {x}^{2}}$ [Ans]