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<body class='hmmessage'><div dir='ltr'>Hi: In what version of scilab did you install scimax?<br><br><div><hr id="stopSpelling">From: pablo_f_7@hotmail.com<br>To: users@lists.scilab.org<br>Date: Sat, 15 Aug 2015 23:05:23 -0300<br>Subject: Re: [Scilab-users] Symbolic computation in Scilab<br><br>
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<div dir="ltr">Hi:<br>I assume that you wanted to calculate the z-transfor of the difference of 7*x1 and 6*x2... And for the limits of your sumation, i also assume your sequence is causal...<br>In theory, if im not making a mistake, X1(z) should be 1/(1-0.33*z^(-1)) and X2(z)=1/(1-0.5*z^(-1))...<br><br>If this is right, the answer should be the difference between them, scaled by 7 and 6 respectively...<br><br>If i do the calculations with maxima i get the expected result...<br><br>However, as i think i told you before, maxima asks for some convergence conditions...<br><br>For example, when i try to do the first summation it ask if |z|-0.33 is positive, negative or zero... this is like giving the ROC of the z transfor, that in this case is |z|>0.33 so you have to answer "p" for positive...<br><br>I don't know is scilab with the scimax toolbox asked for this convergence conditions... but i think that that is the problem yo are having... remebmer that if |z|<a for the sequence a^n*u(n), then the summation does not converge...<br><br>I don't have scimax toolbox installed, so i can't tell you how to continue with it... but with maxima alone the result is ok..<br><br>what happens if you try to disp(x1) and disp(x2)?? are they ok?? <br><br><br><br><br><br> <br><br><div>> Date: Fri, 14 Aug 2015 19:29:36 -0700<br>> From: doole93@gmail.com<br>> To: users@lists.scilab.org<br>> Subject: Re: [Scilab-users] Symbolic computation in Scilab<br>> <br>> Another thing i wanted to ask. When executing a script such as this<br>> Syms n z ;<br>> x1 =(0.33) ^( n )<br>> X1 = %sym_sum (7* x1 *( z ^( - n ) ) ,n ,0 , %inf )<br>> x2 =(0.5) ^( n )<br>> X2 = %sym_sum (6* x2 *( z ^( - n ) ) ,n ,0 , %inf )<br>> X = X1 - X2<br>> disp (X , 'a n s=' )<br>> <br>> i get something like this<br>> <br>> a n s= <br>> <br>> %inf %inf<br>> ==== n ==== n<br>> \ 0.33 \ 0.5<br>> 7 > ----- - 6 > ----<br>> / n / n<br>> ==== z ==== z<br>> n = 0 n = 0<br>> <br>> Since I'm a newbie in Scilab, and I'm also not particularly good with the<br>> mathematical background of the z-transformation (I'm still learning it), is<br>> this the output I should be getting from the sequence of commands above?<br>> <br>> <br>> <br>> --<br>> View this message in context: http://mailinglists.scilab.org/Symbolic-computation-in-Scilab-tp4032673p4032686.html<br>> Sent from the Scilab users - Mailing Lists Archives mailing list archive at Nabble.com.<br>> _______________________________________________<br>> users mailing list<br>> users@lists.scilab.org<br>> http://lists.scilab.org/mailman/listinfo/users<br></div> </div>
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