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Thread: incredibly important and due tomorrow homework

  1. Dec 9th 2007, 03:36 PM #1
    toptoptoptoptop
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    incredibly important and due tomorrow homework

    How do I find the value of x in tan(2x)-4tan(x)=3 ?
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  2. Dec 9th 2007, 03:57 PM #2
    galactus
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    You could use the substitution tan(2x)=\frac{2tan(x)}{1-tan^{2}(x)}

    After you do that, simplify and make the substitution u=tan(x).

    You should get the cubic. 4u^{3}+3u^{2}-2u-3=0

    Solve for u, then find x by taking arctan(u).
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  3. Dec 9th 2007, 04:50 PM #3
    toptoptoptoptop
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    thank you
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