##### 18.15 Solving trigonometric equations using pythagorean identities

### Solving trigonometric equations using pythagorean identities

###### Basic concepts:

- Reference angle
- Find the exact value of trigonometric ratios
- ASTC rule in trigonometry (All Students Take Calculus)
- Pythagorean identities

###### Related concepts:

- Unit circle
- Derivative of trigonometric functions