1.5 Trigonometry

Given that $\theta\,$ is small, use the small angle approximation of $\cos \theta\,$ to show that

\cos(\theta) + \cos^2(2\theta) \approx 5 - 6\theta^2 + 4\theta^4

[3]

Hence find an approximation of $\cos(\theta) + \cos^2(2\theta)$ when $θ=3∘\theta = 3^\circ$

[2]

Calculate the percentage error in your approximation

[2]

1.5 Trigonometry Questions

Given that $\theta\,$ is small, use the small angle approximation of $\cos \theta\,$ to show that

\cos(\theta) + \cos^2(2\theta) \approx 5 - 6\theta^2 + 4\theta^4

[3]

Hence find an approximation of $\cos(\theta) + \cos^2(2\theta)$ when $θ=3∘\theta = 3^\circ$

[2]

Calculate the percentage error in your approximation

[2]