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
Ong Jia Zhi
Ong Jia Zhi

secondary 3 chevron_right A Maths chevron_right Singapore

How to do 9b? Need R-formula?

Date Posted: 5 months ago
Views: 29
Eric Nicholas K
Eric Nicholas K
5 months ago
One way is double angle AND R-formula.
The other way is to convert "1" into sin2x + cos2x.

See 1 Answer

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
2263 answers (Tutor Details)
You can use either double-angle formula followed by R-formula to get the answer or my method below.

EDIT (for the one on top): Change '-3 cos x' to '-3 cos 2x'.