Posted by sh on Saturday, February 27, 2010 at 11:22pm.
(1-sin2x)/cos2x = cos2x/(1+sin2x)
I tried starting from the right side,
and the right side just goes in circle. May I get a hint to start off?
- Calculus - Reiny, Saturday, February 27, 2010 at 11:51pm
First of all since the angle is 2x throughout, let's just use y for 2x
Secondly, you probably want to prove it as an identity, rather than solve it
= cosy/(1+siny) [(1-siny)/(1-siny)]
= cosy(1-siny)/(1- sin^2 y)
= (1- sin 2x)/cos 2x
- Calculus - drwls, Saturday, February 27, 2010 at 11:51pm
cos^2(2x) = 1- sin^2(2x) = cos^2 2x
x can be anything.
That is why it is called an identity
- Calculus - sh, Sunday, February 28, 2010 at 12:00am
Got it, thanks!
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