# Suppose f(x) is differentiable function and if f(x)y + f(y)x = 10, find f'(x).

## Question:

Suppose f(x) is differentiable function and if f(x)y + f(y)x = 10, find f'(x).

## Implicit Differentiation:

Here we will need to take a derivative to find {eq}f'(x). {/eq} However, {eq}f(x) {/eq} is not explicitly isolated, so we must differentiate implicitly. To do this we take the derivative as we know how, but then multiply by {eq}\dfrac{dy}{dx} {/eq} every time we differentiate a term with {eq}y. {/eq}