Implicit Differentiation (AQA A-Level Mathematics): Quizzes

When $y$ is not isolated (e.g. $x^2+y^2=1$)

$\frac{d}{dy} \times \frac{dy}{dx}$

$2y \frac{dy}{dx}$

$\frac{-x}{y}$

$y + x\frac{dy}{dx}$

It leverages the chain rule

$x^2 + y^2 + 5xy = \cos x$

Set it equal to 0

Finding tangent line slopes

Yes, differentiate $\frac{dy}{dx}$ again