New Zealand
Level 8 - NCEA Level 3

# Applications of Pythagorean identities

## Interactive practice questions

By starting with the left hand side, prove that $\frac{1-\cos^2\left(\theta\right)}{\sin\theta}=\sin\theta$1cos2(θ)sinθ=sinθ.

Easy
Approx 2 minutes

Starting with the left hand side, prove the identity $\frac{1-\sin^2\left(x\right)}{\cos x}=\cos x$1sin2(x)cosx=cosx.

### Outcomes

#### M8-6

Manipulate trigonometric expressions

#### 91575

Apply trigonometric methods in solving problems