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Math Help - differentiation

  1. #1
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    differentiation

    RMS Value of Current

    i = 4sin /pit is 2.828A
    (hint given) sin^2 /theta = 1/2 (1-cos 2 /theta)
    see attached for my efforts so far.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by batman121 View Post
    RMS Value of Current

    i = 4sin /pit is 2.828A
    (hint given) sin^2 /theta = 1/2 (1-cos 2 /theta)
    see attached for my efforts so far.
    The mean square current:

    p=\frac{1}{2} \int_0^2 [i(t)]^2~dt\ \ {\rm{Amps}}^2

    (the 1/2 and the limits of integration because the current is periodic with period 2), so putting in the expression for i(t) :

    p=\frac{1}{2} \int_0^2 [4 \sin(\pi t)]^2~dt= 4 \int_0^2 [1- \cos(2 \pi t)]~dt=8

    hence the root mean square is \sqrt{p}=2 \sqrt{2}\approx 2.828\ \ {\rm{Amps}}.

    RonL
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