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Math Help - trigonometric identities

  1. #1
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    trigonometric identities

    Could someone please tell me if I done this correctly?


    Verify the identity

    <br />
cot^2 x - cos^2 x = cot^2 x cos^2 x<br />

    <br />
-cos^2(-x) = cos^2 x <br />
    So:
    <br />
cot^2 x cos^2 x<br />
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  2. #2
    Senior Member vincisonfire's Avatar
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    <br />
cot^2 x - cos^2 x = cot^2 x \cdot cos^2 x<br />
    <br />
\frac{cos^2 x}{sin^2 x}  - cos^2 x = \frac{cos^2 x}{sin^2 x} \cdot cos^2 x<br />
    <br />
\frac{1}{sin^2 x}  - 1 = \frac{cos^2 x}{sin^2 x}<br />
    <br />
cosec^2 x = cot^2 x +1 <br />
    The well known identity you can easily check. Multiply by <br />
sin^2 x<br />
    <br />
1  - sin^2 x  = cos^2 x <br />
    <br />
1   = cos^2 x + sin^2 x <br />
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