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Sun, 28 Nov 2010 23:09:03 +0000
Symbolic Math Integration
http://www.mathworks.com/matlabcentral/newsreader/view_thread/297562#800022
David Egolf
I'm having a problem with the "igrand" statement in Matlab's Symbolic Math toolbox. For example, please refer to the following two programs that I copied and pasted from my "m" files. The only difference between these two programs is that, in the <br>
integrand, the coefficients R1=c1, R2=c2/2, and R3=c3/3. I ran both programs, then made the substitutions indicated in the previous sentence by hand. But the two solutions are different by 1/2*log(6) = 0.896. Am I doing something wrong or is the Symbolic Math "igrand" statement screwed up? I hope somebody can set me straight. My direct email address is <degolf@uidaho.edu>.<br>
Thanks,<br>
David Egolf<br>
<br>
%<br>
% LK_Integration_Using R_Coefficients_Nov_2_2010<br>
clear all<br>
syms F R1 R2 R3<br>
igrand = 1./((R1).*(1(F))+(R2).*(1(F.^2))+(R3).*(1(F.^3)))<br>
y = int(igrand,F)<br>
ys = simple(y)<br>
%<br>
<br>
%<br>
% LK_Integration_Using_C_Coefficients_Nov_9_2010<br>
clear all<br>
syms F c1 c2 c3<br>
igrand = 1./(c1+(c2./2)+(c3./3)((c1).*(F))((c2./2).*(F.^2))((c3./3)...<br>
.*(F.^3)))<br>
y = int(igrand,F)<br>
ys = simple(y)<br>
%

Mon, 29 Nov 2010 00:11:03 +0000
Re: Symbolic Math Integration
http://www.mathworks.com/matlabcentral/newsreader/view_thread/297562#800043
Roger Stafford
"David Egolf" <degolf@uidaho.edu> wrote in message <icunef$svu$1@fred.mathworks.com>...<br>
> I'm having a problem with the "igrand" statement in Matlab's Symbolic Math toolbox. For example, please refer to the following two programs that I copied and pasted from my "m" files. The only difference between these two programs is that, in the <br>
> integrand, the coefficients R1=c1, R2=c2/2, and R3=c3/3. I ran both programs, then made the substitutions indicated in the previous sentence by hand. But the two solutions are different by 1/2*log(6) = 0.896. Am I doing something wrong or is the Symbolic Math "igrand" statement screwed up? I hope somebody can set me straight. My direct email address is <degolf@uidaho.edu>.<br>
> Thanks,<br>
> David Egolf<br>
> <br>
> %<br>
> % LK_Integration_Using R_Coefficients_Nov_2_2010<br>
> clear all<br>
> syms F R1 R2 R3<br>
> igrand = 1./((R1).*(1(F))+(R2).*(1(F.^2))+(R3).*(1(F.^3)))<br>
> y = int(igrand,F)<br>
> ys = simple(y)<br>
> %<br>
> <br>
> %<br>
> % LK_Integration_Using_C_Coefficients_Nov_9_2010<br>
> clear all<br>
> syms F c1 c2 c3<br>
> igrand = 1./(c1+(c2./2)+(c3./3)((c1).*(F))((c2./2).*(F.^2))((c3./3)...<br>
> .*(F.^3)))<br>
> y = int(igrand,F)<br>
> ys = simple(y)<br>
> % <br>
      <br>
See my reply in your duplicate post.<br>
Roger Stafford