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Math Help - Trigonometry proof involving sum and differnece indentity

  1. #1
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    Trigonometry proof involving sum and differnece indentity

    How would I solve the following
    sin^5x=(1/16)(10sinx-5sin3x+sin5x)

    Help is appreciated.
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  2. #2
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    Re: Trigonometry proof involving sum and differnece indentity

    First, you probably mean "prove," not "solve." One solves an equation to find its roots, which are usually few. One proves an identity, which is an equality that holds for all values of x.

    Using the formulas for the sine and cosine of the sum of angles, try to express sin(3x) and sin(5x) through powers of sin(x).
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