# Thread: How to get the critical numbers?

1. ## How to get the critical numbers?

Question:
$x(4-x^2)^\frac{1}{2}$

Attempt:
$y'= (x) * \frac{1}{2}(4-x^2)^\frac{-1}{2}*(-2x)+(4-x^2)^\frac{1}{2}*(1)$

After this step i dont know how to simplify?