# How do you find (dy)/(dx) given 2x^2+y^2=4?

Nov 4, 2016

$\frac{d}{\mathrm{dx}} \left(2 {x}^{2} + {y}^{2}\right) = \frac{d}{\mathrm{dx}} \left(4\right)$

$4 x + 2 y \left(\frac{\mathrm{dy}}{\mathrm{dx}}\right) = 0$

$2 y \left(\frac{\mathrm{dy}}{\mathrm{dx}}\right) = - 4 x$

$\frac{\mathrm{dy}}{\mathrm{dx}} = \frac{- 4 x}{2 y}$

$\frac{\mathrm{dy}}{\mathrm{dx}} = \frac{- 2 x}{y}$

Hopefully this helps!