Power rule for differentiation: The power rule states that when differentiating functions with powers, you bring down the exponent as coefficient and reduce it by 1. For example, when differentiating $x^3$, you get $3x^2$.
Trig identities: Trigonometric identities are equations involving trigonometric functions that hold true for all values of the variable. These identities can be used to simplify expressions or solve trigonometric equations.
Chain rule: The chain rule is a formula for computing the derivative of a composition of two or more functions. It allows us to find the derivative of composite functions like $f(g(x))$.