# i. Using the expansion of cos(3x x) and cos(3x + x), prove that ii. Hence show that -~ (cos 2x - cos 4x) = sin 3x sin.x.

Chapter 5, Review Exercises #15

i. Using the expansion of cos(3x − x) and cos(3x + x), prove that

ii. Hence show that

## This problem has been solved!

Do you need an answer to a question different from the above? Ask your question!

**Related Book For**

## Cambridge International AS & A Level Mathematics Pure Mathematics 2 & 3 Coursebook

1st Edition

**Authors:** Sue Pemberton, Julianne Hughes, Julian Gilbey

**ISBN:** 9781108407199