## Compound Angle Formulae New Topic: Compound Angle Formulae, MiA Unit 2 Ch3

By the end of this topic you will be able to:

• know and apply the addition formulae:
sin(A+B) = sinAcosB + cosAsinB
sin(A–B)  = sinAcosB – cosAsinB
cos(A+B) = cosAcosB – sinAsinB
cos(A–B) = cosAcosB + sinAsinB

• know and apply the double angle formulae:
sin2A  = 2sinAcosA
cos2A = cos2A – sin2A = 2cos2A – 1

• apply trigonometric formulae in solution of geometric problems

• solve trigonometric equations using compound angle formulae

### 10 Responses

1. Thursday 4 December, Periods 2 & 3

Revision of trig exact values.
Proof of sin(A+B) then p155 Ex2

2. All above completed.

3. Friday 5 December, Period 2

Exact values starter then complete Ex3 from Q3 on.

4. Most of class reached proof questions at end of Ex.
Will come back to better problems when all formulae covered.

5. Monday 8 December, Period 6

Double Angle Formulae, Ex4A.

Derive formulae then complete Q1,2,4,8,9,11-13.

6. CAST rule starter to begin then rattled through examples above except Q11, 12b & 13 – will complete next lesson.

Look at further trig identities.

7. Wednesday 10 December, Period 6

Revise trig equations: CAST rule, radians, etc.

Examples then Ex4 from p53.

8. Thursday 11 December, Periods 2 & 3

Solving trig equations.

p54 Ex5 Q2,3,4
p55 Ex6 Q1-6
p161 Ex5 All Q’s

Homework: Integration
Due: Thursday 18 December

9. Spent some time on an Exact Values starter exercise.
All pupils working on first half of p161 Ex5.
Homework issued.

10. Friday 12 December, Period 2

Complete p161 Ex5 then some from p55 Ex6.