In order to solve trigonometric equations, you sometimes need to apply identities (i.e., rules that state what common expressions are equal to). This video walks through some of the most important trig identities to know and uses them to solve equations.

**Lesson 2: Solving equations and inequalities**

- Why solve equations?
- Solving equations: Quadratics
- Exercises: Solve quadratic equations
- Solving equations: Absolute values
- Exercises: Solve equations involving absolute value
- Solving equations: Polynomials
- Exercises: Solve polynomial equations
- Solving equations: Rational expressions
- Exercises: Solve equations involving rational expressions
- Solving equations: Exponents
- Exercises: Solve exponential equations
- Solving equations: Logs
- Exercises: Solve logarithmic equations
- Solving equations: Trigonometric functions 📝
- Trig identities
- Exercises: Solve trigonometric equations
- Why solve inequalities?
- Solving inequalities
- Exercises: Solve inequalities