Power Rule

The Power Rule is a rule in calculus for finding the Derivative of $x$ raised to a constant power:

$\frac{d}{dx} x^n = n x^{n-1}$

For example, $\frac{d}{dx} x^2 = 2x$ and $\frac{d}{dx} x^3 = 3x^2$. It's one of the rules that makes derivatives quick to work out by hand, like when calculating the gradient of a squared error loss in Gradient Descent.

Logarithms have a rule with the same name, $\log_b(M^p) = p \cdot \log_b(M)$, which is covered in Logarithm Properties.