If $y + \cos y = x^2$, what is $\frac{dy}{dx}$?

Explanation

1. 01

   Differentiate both sides: $\frac{dy}{dx} - \sin y\frac{dy}{dx} = 2x$.

2. 02

   $(1 - \sin y)\frac{dy}{dx} = 2x$, so $\frac{dy}{dx} = \frac{2x}{1 - \sin y}$.