- #1
paul18
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Homework Statement
Previous part of the question I have solved:
Express cos(2x) in terms of sin(x):
I got this answer:
cos(2x)=1-2sin2(x)
Hence or otherwise solve the equation
cos(x) + 3sin(x/2) = 2
Homework Equations
Double angle formulae:
cos(2x)=cos(2x) - sin(2x)
sin(2x)=2sin(x)cos(x)
The Attempt at a Solution
So basically I'm doing revision on trig, and I know I've come across this problem before, where you are presented with a full angle and a half angle, but I have failed to find an example. It's something to do with halving a double angle formula I think but I can't even start it. How do I get rid of the half angle? I know I should show an attempt, but I can't even start it off. Just a refresher on how to remove half angles would be great thanks :)
(Yes i have read the rules but this problem is difficult to put into that format properly)