Find : $ dy/dx, y=\sqrt{4x^2 - 7x - 2}$ The problem says Find $dy/dx,  y=\sqrt{4x^2 - 7x - 2}$
So far I changed it to $(4x^2 - 7x - 2)^{1/2}$
I don't know where to go from there.

If $y = \sqrt{4x^2 - 7x - 2}$
then 
$$\frac{dy}{dx} = \frac{d}{dx}(4x^2 - 7x - 2)^{\frac{1}{2}}
\\
$$
$$
=\frac{1}{2}\frac{d}{dx}(4x^2 - 7x - 2) \times (4x^2 - 7x - 2)^{\frac{-1}{2}}
$$
$$
= \frac{8x-7}{2\sqrt{4x^2 - 7x - 2}}
$$
using the chain rule.
That is, if we have a function $y = u^{\frac{1}{2}}$ then $$\frac{dy}{dx} = \frac{dy}{du}\times\frac{du}{dx}$$
