Compound and double angle formulae

What you'll learn

1. 1

   Imagine you have a superhero identity that's a combination of two smaller heroes — compound angle formulae are like that for sine, cosine and tangent!

2. 2

   Here's how sin(45° + 30°) works — we use the formula instead of adding the angles first.

3. 3

   Let's find sin(75°) using the compound angle formula.

4. 4

   What is the formula for sin(A + B)?

5. 5

   Drag the angle values to complete sin(60° + 45°) using the formula.

6. 6

   If you know sin30° = ½ and cos30° = √3/2, what is sin(30° + 30°)?

7. 7

   Now try cos(2A) — the double angle formula!