SSSI Week 4: Trig Identities, Compound and Double Angle, R formula

Year 2 Trig Identities and Modelling (Chapter 7)

This is often the hardest part of your A level to master.

Make good use of the formula booklet so that you don't have to remember everything (although it is advisable to remember the double angle rearrangements that incorporate sin^2 or cos^2 only).

You are not given tan^2 + 1 = sec^2 or cot^2 + 1 = cosec^2 identities so you need to remember these.

sin 3A can be found using sin (2a + a) which also involves working out sin 2a as well, so multiple steps.

The more questions of these you can do the better.