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Adding waveforms

  1. Mar 13, 2010 #1
    say i have the following waveforms

    V1=10cos(wt)
    V2=20sin(wt)

    and i am told to find an analytic expression for the resulting voltage waveform

    fristly i found the V1+V2 add the two phasors at t= 0 to get 22.4 and then i found theta which is 26.5 (tan^-1(10/20)) but now im confused will the expression be:

    V=22.4sin(wt+26.5)

    or

    V=22.4cos(wt+26.5)
     
  2. jcsd
  3. Mar 13, 2010 #2

    mathman

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    Science Advisor

    You can use the cos(a+b) and sin(a+b) expansions and see which one gives you the original V1 and V2.
     
  4. Mar 13, 2010 #3

    Born2bwire

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    Gold Member

    At t=0 it is trivial to calculate the result of the original voltages.

    At t=0, V = 10. So which of the two expressions for V that you have satisfy this relationship?
     
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