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Homework Help: Addition of AC current and compound angle theory

  1. Jan 8, 2010 #1
    1. The problem statement, all variables and given/known data

    two alternating currents I1 and I2 flow into a circuit node,the output current I is given by adding I1 and I 2.

    find I and t, when I1 and I2 are as follows

    2. Relevant equations

    I1=5sin(50t +Pi/3)

    I2=6cos50t

    3. The attempt at a solution
    i1=sin(a+b)=sina.sinb+cosa.cosb
    i1=sin50t x cos 60 + sin60 x cos60t x by 1/2 gives
    i1=2.5sin50t + 4.33 x cos50t







    Hi guys help required on above question please not sure where this progresses

    thanks
     
  2. jcsd
  3. Jan 8, 2010 #2

    rock.freak667

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    Homework Helper

    So you have [itex]I_1=\frac{1}{2}sin50t+\frac{\sqrt{3}}{2}cos50t[/itex] and [itex]I_2=6cos50t[/itex]

    So just add them now, and group the like terms.

    You will have something like Asin50t+Bcos50t to put in the form Rsin(50t+α)
     
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