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Math Help - trigonometry compund angle formula

  1. #1
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    trigonometry compund angle formula

    Prove that  sec^2 \theta + cosec^2 \theta \equiv 4cosec^2 2\theta

    Really not sure about using the compound angle formula. Thanks for any help
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  2. #2
    MHF Contributor red_dog's Avatar
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    \sec^2\theta+\csc^2\theta=\frac{1}{\cos^2\theta}+\  frac{1}{\sin^2\theta}=\frac{\sin^2\theta+\cos^2\th  eta}{\sin^2\theta\cos^2\theta}=

    =\frac{1}{\sin^2\theta\cos^2\theta}=\frac{4}{4\sin  ^2\theta\cos^2\theta}=\frac{4}{\sin^22\theta}=4\cs  c^22\theta
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  3. #3
    Junior Member
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    Finding the values

    Thanks, I managed to work out what to do in the end. Can anyone tell me what you would do to find \theta ?
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  4. #4
    Senior Member pacman's Avatar
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    aaahh, you post this as a trigonometric equation? i thought it was an identity as as solved by red_dog, YOUR post is an identity . . . .
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