Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.


secondary 3 | A Maths
One Answer Below

Anyone can contribute an answer, even non-tutors.

Answer This Question

secondary 3 chevron_right A Maths chevron_right Singapore

pls help

Date Posted: 9 months ago
Views: 162

See 1 Answer

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
5951 answers (Tutor Details)
We use a series of double-angle formulae to do this question. Note that the angle pair does not have to be specifically 2x and x; as long as one angle is twice of another, the formula remains valid.

In other words,
sin 2x = 2 sin x cos x
sin 4x = 2 sin 2x cos x

(because 2x is twice of x while 4x is twice of 2x)