You will be expected to be able to prove a trigonometric identity such as the examples below. In the videos I show you how to set out an identity and what to look for.

Learn the Pythagorean identities below and then try the examples that follow. This is a tricky topic and one that I find students give in too quickly, be patient and it will come. Hopefully this will be a start for you.

Pythagorean Identities:

  • sin2θ + cos2θ ≡ 1
  • 1 + tan2θ ≡ sec2θ
  • 1 + cot2θ ≡ cosec2θ

Example 1

Example 2

Example 3

Example 4

Example 5

Example 6

Example 7

Example 8