Originally Posted by

**Hydralisk** Hi, I'm working through some integral problems, and I've been able to achieve the correct solution of

$\displaystyle y=\sqrt{2c-x^{2}}$

I am then being asked to check my solution by differentiating it, I've also been given the solution to doing this, but I can't understand one step of the solution.

$\displaystyle f'\left[\left((2c-x^{2})^{\frac{1}{2}\right]=\frac{1}{2}(2c-x^{2})^{\frac{-1}{2}}(-2x)$

Where does the $\displaystyle (-2x)$ come from during differentiation?

Many thanks,

Shayne.