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Math Help - How'd they get cos out here?

  1. #1
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    How'd they get cos out here?

    Hi folks,

    Firstly this is the page I'm looking at to try and learn some trig,

    SparkNotes: SAT Subject Test: Math Level 1: Trigonometric Identities

    On this page some of their working has got me stumped.

    The question goes as follows

    (\cos\theta \times \tan\theta)  /  (\sin\theta -\cos\theta^2)

    In their working, they re write this as follows

    \frac{\cos\theta \times \tan\theta}{\sin\theta} - \cos\theta^2

    My question is - How did they get the \cos\theta^2 out from under the fraction? Shouldn't it be under there instead of out seperately?

    Why isn't it

    \frac{\cos\theta \times \tan\theta}{\sin\theta - \cos\theta^2}

    Thanks folks.
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  2. #2
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    Quote Originally Posted by Peleus View Post
    Hi folks,

    Firstly this is the page I'm looking at to try and learn some trig,

    SparkNotes: SAT Subject Test: Math Level 1: Trigonometric Identities

    On this page some of their working has got me stumped.

    The question goes as follows

    (\cos\theta \times \tan\theta) / (\sin\theta -\cos\theta^2)

    In their working, they re write this as follows

    \frac{\cos\theta \times \tan\theta}{\sin\theta} - \cos\theta^2 Mr F says: This is wrong.

    My question is - How did they get the \cos\theta^2 out from under the fraction? Shouldn't it be under there instead of out seperately?

    Why isn't it

    \frac{\cos\theta \times \tan\theta}{\sin\theta - \cos\theta^2} Mr F says: This is right.

    Thanks folks.
    ..
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