Hi all, I am stuck on proving these two problems: (csc theta - sin theta)^2 = cot^2theta - cos^2theta and (1+cos2theta/cos^2theta)=2 I know I need to use double angle identities in the second one, but I have been stuck on how to get going.
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Originally Posted by Bikkstah Hi all, I am stuck on proving these two problems: (csc theta - sin theta)^2 = cot^2theta - cos^2theta and (1+cos2theta/cos^2theta)=2 I know I need to use double angle identities in the second one, but I have been stuck on how to get going. .
Can anyone help with (1 + Cos2theta/cos^2theta)=2? I know it's true by setting theta equal to a real angle like 30 degrees, but I don't know how to prove it using just identities.
Originally Posted by Bikkstah (1+cos2theta/cos^2theta)=2 Use the identity Spoiler: This cancels down to 2
Last edited by e^(i*pi); Apr 2nd 2010 at 03:19 AM. Reason: sign error in solution
Thank you both so much!
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