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Math Help - solving trigonometric equations

  1. #1
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    solving trigonometric equations

    for 0<a<360 i need to find 'a' from sec^2(a) = 4tan(a)-2 any help would be much appreciated thanks
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  2. #2
    Eater of Worlds
    galactus's Avatar
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    Rewrite:

    1-tan^{2}(a)=4tan(a)-2

    Now, bring it all to one side and make a u sub to turn it into a quadratic.

    Let u=tan(a)
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  3. #3
    MHF Contributor
    Grandad's Avatar
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    Sec and tan

    Shouldn't that be
    1+tan^2(a)=4tan(a)-2?

    You can remember it by starting with
    sin^2(a)+cos^2(a)=1
    and then dividing both sides by cos^2(a)
    to get
    tan^2(a)+1=sec^2(a)
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