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Homework Help: Trig Identities

  1. Apr 18, 2010 #1
    1. The problem statement, all variables and given/known data
    Verify that each equation is an identity- directions
    Problem- csc(A-B)=secB
    ---------------- <<< divide bar
    2. Relevant equations

    well i tried to put in terms of sin cos and i've gotten stuck

    3. The attempt at a solution

    i started off by disributing i.e.>> cscA-cscB=secB/sinA-cosAtanB
    next i changed tan to sin/cos and cancelled out cos so i was left with cscA-cscB=sec/sinA-sinB

    changed csc to 1/sinA-1/sinB=sec/sinA-sinB

    changed sec to 1/cos so i flipped and multiplied 1/sinA-sinB and got 1/sinA-1/sinB= 1/sincosA-sincosB and im stuck here..... help please
  2. jcsd
  3. Apr 18, 2010 #2


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    Just to be clear, the problem you're trying to solve is to verify the identity

    [tex]\csc(A-B)=\frac{\sec B}{\sin A-\cos A \tan B}[/tex]

    right? Your post is kind of hard to read.

    Your very first step is wrong because [itex]\csc(A-B) \ne \csc A - \csc B[/itex]. Try writing it in terms of sin(A-B) first and go from there.
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