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Please help me plot this equation

  1. Aug 19, 2011 #1
    please help me plot this equation!!

    A = (2n-2 +2n-3+ {n-4i=0 [(-1) n-1-i ]*[2i] } )*B/(2n-2n-1- 2n-2-{n-3i=0 [((-1)n-i ) *2i]})

    maybe taking b along x axis, n along y axis and a along z axis.
    Please post few software or utility name to help me out. But it would be equally useful if someone gives the plotted graph itself.

    ** if any one of you around has SCILAB please post some code for plotting this function.
    The basic problem i face is how am i supposed to add summation/sigma ?
    Last edited: Aug 19, 2011
  2. jcsd
  3. Aug 21, 2011 #2
    Re: please help me plot this equation!!

    Your notation is a little ambiguous. Here's what I think it is:

    [tex]a[\text{n$\_$},\text{b$\_$}]\text{:=}\left(2^{n-2}+2^{n-3}+\left(\sum _{i=0}^{n-4} \left((-1)^{n-1-i}\right) 2^i\right) \right)\frac{b}{2^n-2^{n-1}-2^{n-3}-\sum _{i=0}^{n-3} \left(\left((-1)^{n-1} 2^i\right)\right)}[/tex]

    No way you can hook-up with a machine running Mathematica? Try and find one:

    I'll leave it up to you to run the code if you wish.
    Last edited: Aug 21, 2011
  4. Aug 21, 2011 #3
    Re: please help me plot this equation!!

    If n>=3 and I haven't made a mistake then Jackmell's result simplifies to

    -((8*(-1)^(3*n)*b + 2^n*(-9 + (-1)^(2*n))*b)/(-24*(-1)^n + 3*2^n*(3 + 2*(-1)^n)))

    Perhaps you can plot that in Scilab.
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