Inverse Trigonometric Functions:Inverse trigonometric functions, such as arcsin, arccos, and arctan, are used to find the angle when the ratio of the sides of a right triangle is known.
Trigonometric Substitution: Trigonometric substitution is a technique used in calculus to simplify integrals involving square roots of quadratic expressions by replacing the variable with a trigonometric function.
Pythagorean Identity: The Pythagorean identity states that the sum of the squares of the sine and cosine of an angle is equal to 1, which is useful in trigonometric substitution.