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Derivative of trig functions

  1. Mar 2, 2013 #1
    1. The problem statement, all variables and given/known data

    y = √sinx

    3. The attempt at a solution

    y' = [(sinx)1/2]'
    y' = 1/2 (sinx)-1/2 (sinx)'
    y' = 1/2 cosx (sinx)-1/2

    However book says the answer should be:

    1/2 cotx (√sinx)
  2. jcsd
  3. Mar 2, 2013 #2
    Hint: what is the definition of cotan(x)?
  4. Mar 2, 2013 #3


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    Homework Helper

    Your answer is right. The book's answer is also right. cot(x)=cos(x)/sin(x). Try to convince yourself they are both right.
  5. Mar 2, 2013 #4
    1/tanx ?
  6. Mar 2, 2013 #5
    And what is tan in terms of cos and sin?
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