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Math Help - Double angle formulas of seceant, cosecant, and cotangent

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    Double angle formulas of seceant, cosecant, and cotangent

    How do they differ from the sine, cosine, and tangent double angle formulas, if at all? I've been asked on homework to find the trigonometric function of (ex: sec2\theta). I know how to find it, I'm just not sure if there's a different double angle identity I have to use when using the inverse of cosine.
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    Bar0n janvdl's Avatar
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    Quote Originally Posted by mathgeek777 View Post
    How do they differ from the sine, cosine, and tangent double angle formulas, if at all? I've been asked on homework to find the trigonometric function of (ex: sec2\theta). I know how to find it, I'm just not sure if there's a different double angle identity I have to use when using the inverse of cosine.
    sec 2x = \frac{1}{cos 2x}
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    Ok thanks

    I'm gonna run some answers by you guys real quick

    Triangle lengths :
    opposite = 3
    adjacent = 4
    hypotenuse = 5

    For sec2\theta I got \frac{25}{7}

    For csc2\theta I got \frac{25}{24}

    For cot2\theta I got \frac{7}{24}
    Last edited by mathgeek777; January 26th 2008 at 11:51 AM. Reason: added cotangent answer
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    Bar0n janvdl's Avatar
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    Quote Originally Posted by mathgeek777 View Post
    Ok thanks

    I'm gonna run some answers by you guys real quick

    Triangle lengths :
    opposite = 3
    adjacent = 4
    hypotenuse = 5

    For sec2\theta I got \frac{25}{7}

    For csc2\theta I got \frac{25}{24}

    For cot2\theta I got \frac{7}{24}
    Looks fine to me
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  5. #5
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    Quote Originally Posted by janvdl View Post
    Looks fine to me
    Awesome! Thanks for your help
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  6. #6
    Bar0n janvdl's Avatar
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    Quote Originally Posted by mathgeek777 View Post
    Awesome! Thanks for your help
    You're welcome
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