Mathematics A-Level
Pythagorean identity
What Pythagorean identity means in Mathematics A-Level, as defined for WJEC.
Definition of Pythagorean identity
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Reference: WJEC
cos²θ + sin²θ = 1, which applies Pythagoras' theorem to the right-angled triangle formed in the unit circle.
Topics that use Pythagorean identity
- Trigonometry (AS Unit 1: Pure Mathematics A) (WJEC A-Level)
Related terms
- area of a triangle
- CAST diagram
- cosine rule
- equation solving
- factorisation
- multiple-angle equations
- periodic solutions
- principal value
Using Pythagorean identity in the exam
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