# What is the derivative of y=x (4-x)^.5?

$\frac{\mathrm{dy}}{\mathrm{dx}} = \frac{8 - 3 x}{2 \sqrt{4 - x}}$
$\frac{\mathrm{dy}}{\mathrm{dx}} = 1 \times {\left(4 - x\right)}^{0.5} + 0.5 {\left(4 - x\right)}^{0.5 - 1} \left(- 1\right) \times x$
$\frac{\mathrm{dy}}{\mathrm{dx}} = {\left(4 - x\right)}^{0.5} - \frac{0.5 x}{4 - x} ^ 0.5$
$\frac{\mathrm{dy}}{\mathrm{dx}} = \frac{8 - 3 x}{2 \sqrt{4 - x}}$