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Simplifying after applying chain rule

  1. Oct 1, 2011 #1
    1. The problem statement, all variables and given/known data

    http://images.calcchat.com/solutionart/etf5e/03/d/se03d01063.png [Broken]

    2. Relevant equations

    3. The attempt at a solution
    I get to the third row, but cant simplify (Sin2θ)(Cos2θ). I'm looking at the trigonometric double angle formulas, and still cant figure out how the final answer came to be 1/2(Sin4θ)
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Oct 1, 2011 #2


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    2sin(x)cos(x) = sin(2x) .

    That should help.
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