Trigonometry

1. Identities

1.1. Negative Angles

1.1.1. Special Angles

1.1.1.1. Evaluation Questions

1.1.1.1.1. Given info on positive/negative trigo. Identify the quadrant. ACTS

1.1.1.1.2. Use Pythagoras' Theorem to look for missing length. If tangent ratio is a, this means ratio of (o)/(a) is a/1. (h) becomes sqrt(a^2+1)

1.1.1.1.3. Ensure that you insert negative sign when the trigo is applied on the angle not in the first or same quadrant.

1.2. Acute and Obtuse Angles

1.3. Addition Formula

1.3.1. Addition Formula

1.4. Double Angle

2. Solving

2.1. Factorise or change to the same trigo

2.2. Find ACTS

2.2.1. Find basic angle, using only positive values

2.3. Update range of angle

2.4. Write down all possible answers based on ACTS