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Math Help - How to find x(0) for X(s)

  1. #1
    Member moonnightingale's Avatar
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    How to find x(0) for X(s)

    Plz help me to select correct option
    Attached Thumbnails Attached Thumbnails How to find x(0) for X(s)-2.gif  
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  2. #2
    A Plied Mathematician
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    Re: How to find x(0) for X(s)

    Use the Initial Value Theorem (scroll down).
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  3. #3
    Member moonnightingale's Avatar
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    Re: How to find x(0) for X(s)

    Thanks can u kindly further explain and tell me answer
    i am getting infinity/infinity

    plz guide me
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  4. #4
    Member moonnightingale's Avatar
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    Re: How to find x(0) for X(s)

    I have solved it with initial value theorem , kindly cross check it

    s^2 (s^-1+10s^-2) / s^3 (1+s^-2+4s^-3)

    now sF(s)

    i am left with
    (s^-1+10s^-2) / s^3 (1+s^-2+4s^-3)

    and now putting s--->infinity
    0/1= 0

    so x(0) = 0 Is this correct answer plz tell me
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  5. #5
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    Re: How to find x(0) for X(s)

    Quote Originally Posted by moonnightingale View Post
    I have solved it with initial value theorem , kindly cross check it

    s^2 (s^-1+10s^-2) / s^3 (1+s^-2+4s^-3)

    now sF(s)

    i am left with
    (s^-1+10s^-2) / s^3 (1+s^-2+4s^-3)

    and now putting s--->infinity
    0/1= 0

    so x(0) = 0 Is this correct answer plz tell me
    You have the correct answer, but I'm not so sure about your method. You must compute

    \lim_{s\to\infty}\frac{s(s+10)}{s^{3}+s+4}=\lim_{s  \to\infty}\frac{s^{2}+10s}{s^{3}+s+4}=\lim_{s\to \infty}\frac{s^{-1}+10s^{-2}}{1+s^{-2}+4s^{-3}}.

    Now you can conclude what you concluded.
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  6. #6
    Member moonnightingale's Avatar
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    Re: How to find x(0) for X(s)

    Thanks a lot
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