Introduction to TrigonometryStep 1 of 3
Question
Prove (1 − cos²θ)/sinθ = sinθ.
(1 − cos²θ)/sinθ
→?
sin²θ + cos²θ = 1
Where should the proof begin?
What you will learn
Prove a trigonometric identity by simplifying one side using reciprocal and Pythagorean identities.
Common mistake to avoid
Starting by writing LHS equals RHS assumes the statement being proved and often leads to circular working.
Make this mistake visibleHelpful?