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Homework Help: Prove identity

  1. Feb 13, 2009 #1
    1. The problem statement, all variables and given/known data

    Prove:
    csc2@= 1/(1-(sin@-cos@)^2

    2. Relevant equations



    3. The attempt at a solution

    I'm stuck cant seem to work this on out. I'm not seeing the relationship between the two
     
  2. jcsd
  3. Feb 13, 2009 #2
    I tried again and ended up with 1/sin2@=1/-sin2@

    erg
     
  4. Feb 13, 2009 #3

    HallsofIvy

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    On the right side, [itex](sin(\theta)- cos(\theta))^2= sin^2(\theta)- 2sin(\theta)cos(\theta)+ cos^2(\theta)[/itex]
    [itex]= 1- 2sin(\theta)cos(\theta)[/itex]
    so [itex]1- (sin(\theta)- cos(\theta))^2= 2sin(\theta)cos(\theta)[/itex]

    Do you recognize that as [itex]sin(2\theta)[/itex]?
     
  5. Feb 13, 2009 #4
    mental error I got it
     
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