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Math Help - Trig

  1. #1
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    Trig



    Diagonals = 2 units

    (a) Find AD and DC in terms of θ.

    (b) Show that DX = sin2θ.

    (c) Hence deduce that sin2θ = 2sinθcosθ

    Could someone please show me how to start this question? I've been pondering on it for ages.
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  2. #2
    A riddle wrapped in an enigma
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    Quote Originally Posted by xwrathbringerx View Post


    Diagonals = 2 units

    (a) Find AD and DC in terms of θ.

    (b) Show that DX = sin2θ.

    (c) Hence deduce that sin2θ = 2sinθcosθ

    Could someone please show me how to start this question? I've been pondering on it for ages.
    Hello xwrath..,

    \sin \theta=\frac{DC}{2}

    \boxed{DC=2\sin \theta}

    \cos \theta=\frac{AD}{2}

    \boxed{AD=2\cos \theta}

    \sin \theta=\frac{DX}{2\cos \theta}

    \boxed{DX=2\sin \theta \cos \theta}

    \boxed{\sin 2\theta=2\sin \theta \cos \theta}

    \boxed{DX=\sin 2\theta}
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