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en-us2017 Maplesoft, A Division of Waterloo Maple Inc.Maplesoft Document SystemSat, 18 Nov 2017 21:23:16 GMTSat, 18 Nov 2017 21:23:16 GMTThe latest comments and answers added to MaplePrimeshttp://www.mapleprimes.com/images/mapleprimeswhite.jpgMaplePrimes - Newest Comments
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Use just central differences
https://www.mapleprimes.com/questions/223264-Substitute-And-Solve-System-Of-Equations-?ref=Feed:MaplePrimes:New Comments#comment243582
<p><a href="/questions/223264-Substitute-And-Solve-System-Of-Equations-#comment243581">@Zeineb</a> </p>
<p>It seems that the second derivatives are approximated with central differences, but the first derivative is approximated with a forward difference. I changed that to a central difference, and the case where I couldn't get a solution (nX=nY=8) now solves.</p>
<p>When I examined that case for nX=Ny=3, where I could reduce the equations to two in two unknowns, and obtain an implicitplot, now the curves intersect. However, there are multiple intersections, so determining programmatically which of the many possible solutions are the right ones will be difficult.</p>
<p>But it would appear that using two different types of differences for the derivatives was not appropriate.</p>
<p><a href="/questions/223264-Substitute-And-Solve-System-Of-Equations-#comment243581">@Zeineb</a> </p>
<p>It seems that the second derivatives are approximated with central differences, but the first derivative is approximated with a forward difference. I changed that to a central difference, and the case where I couldn't get a solution (nX=nY=8) now solves.</p>
<p>When I examined that case for nX=Ny=3, where I could reduce the equations to two in two unknowns, and obtain an implicitplot, now the curves intersect. However, there are multiple intersections, so determining programmatically which of the many possible solutions are the right ones will be difficult.</p>
<p>But it would appear that using two different types of differences for the derivatives was not appropriate.</p>
243582Sat, 18 Nov 2017 21:11:08 Zrlopezrlopez@tomleslie
I agree with you, there is somet...
https://www.mapleprimes.com/questions/223264-Substitute-And-Solve-System-Of-Equations-?ref=Feed:MaplePrimes:New Comments#comment243581
<p><a href="/questions/223264-Substitute-And-Solve-System-Of-Equations-#comment243558">@tomleslie</a> </p>
<p>I agree with you, there is something not clear which option 1 or 2 is correct and why when we change the boundary condition one get the solution </p>
<p><a href="/questions/223264-Substitute-And-Solve-System-Of-Equations-#comment243558">@tomleslie</a> </p>
<p>I agree with you, there is something not clear which option 1 or 2 is correct and why when we change the boundary condition one get the solution </p>
243581Sat, 18 Nov 2017 19:58:11 ZZeinebZeinebSyntax
https://www.mapleprimes.com/questions/223281-How-Do-I-Draw-Contour-Plot-Of-The-Function?ref=Feed:MaplePrimes:New Comments#comment243580
<p><a href="/questions/223281-How-Do-I-Draw-Contour-Plot-Of-The-Function#comment243579">@assma</a> It is necessary to remove the square brackets and put the multiplication sign where it was missed:<br>
<strong>restart;<br>
f:=(x,y)->exp(-0.96374054*x)*sin(2*Pi*y)*((-0.96374054)^2-4*Pi^2)/(2*Pi);<br>
plots:-contourplot(f(x,y), x=-0.5..1.5, y=-0.5..1.5, numpoints=10000);</strong></p>
<p> </p>
<p><a href="/questions/223281-How-Do-I-Draw-Contour-Plot-Of-The-Function#comment243579">@assma</a> It is necessary to remove the square brackets and put the multiplication sign where it was missed:<br>
<strong>restart;<br>
f:=(x,y)->exp(-0.96374054*x)*sin(2*Pi*y)*((-0.96374054)^2-4*Pi^2)/(2*Pi);<br>
plots:-contourplot(f(x,y), x=-0.5..1.5, y=-0.5..1.5, numpoints=10000);</strong></p>
<p> </p>
243580Sat, 18 Nov 2017 19:09:32 ZKitonumKitonumf:=(x,y)->[(e)^(-0.96374054* x) (sin(2 *Pi *y) ...
https://www.mapleprimes.com/questions/223281-How-Do-I-Draw-Contour-Plot-Of-The-Function?ref=Feed:MaplePrimes:New Comments#comment243579
<p>f:=(x,y)->[(e)^(-0.96374054* x) (sin(2 *Pi *y) )((-0.96374054)^(2)-4* Pi^(2))]/(2 *Pi) on [-0.5,1.5]<sup>2 </sup>, why contour plots of this function in maple18 is different on contour plots of this function in matlab?</p>
<p>f:=(x,y)->[(e)^(-0.96374054* x) (sin(2 *Pi *y) )((-0.96374054)^(2)-4* Pi^(2))]/(2 *Pi) on [-0.5,1.5]<sup>2 </sup>, why contour plots of this function in maple18 is different on contour plots of this function in matlab?</p>
243579Sat, 18 Nov 2017 17:17:05 Zassmaassmauses
https://www.mapleprimes.com/questions/223284-Generalising-To-Arbitrary-Curvilinear?ref=Feed:MaplePrimes:New Comments#comment243578
<p><a href="/questions/223284-Generalising-To-Arbitrary-Curvilinear#comment243576">@jacobBN</a> </p>
<p>With <strong>uses </strong>in a procedure, the package is not loaded in memory; instead, the necessary functions are invoked by their long names.<br>
<strong>with(</strong>packagename<strong>)</strong> can be used only at top-level (i.e. not inside a procedure).</p>
<p><a href="/questions/223284-Generalising-To-Arbitrary-Curvilinear#comment243576">@jacobBN</a> </p>
<p>With <strong>uses </strong>in a procedure, the package is not loaded in memory; instead, the necessary functions are invoked by their long names.<br>
<strong>with(</strong>packagename<strong>)</strong> can be used only at top-level (i.e. not inside a procedure).</p>
243578Sat, 18 Nov 2017 16:24:19 Zvvvv||
https://www.mapleprimes.com/questions/223277-Why-Is-This-Happening-In-Maple?ref=Feed:MaplePrimes:New Comments#comment243577
<p><a href="/questions/223277-Why-Is-This-Happening-In-Maple#comment243572">@mapleatha</a> You have used the infix || elsewhere, in examples where it acts the same as `cat`. You used it for concatenation.</p>
<p>In your other, earlier Question you also had a rational value. I asked in my Answer there whether you needed that to be typeset (pretty-printed) in 2-D Math, rather that the as like "1/2" in 1-D text. You didn't confirm there. And now here you suddenly say that aspect is key.</p>
<p>It's not helpful if you don't give a complete description of what your trying to accomplish, at the start.</p>
<p>I'm not trying to berate you. It's a very common situation on Mapleprimes. People ask about a technical difficulty in an approach they've decided is good for some goal, without telling us all the requirements. Then there's a big circus as we try and dig down to get the true requirements out of them, so that we could suggest a quite different but better overall approach.</p>
<p>This current Question has turned out to be simply a duplicate of another two Questions asked by you, asked close together. Please don't submit three duplicates like that because it splits the value, confuses readers, and separates detail unnecessarily. Please just ask followups details/comments/subcases to Replies/Comments on the original.</p>
<p>You have deleted a comment to which I had responded above. Now my response looks out of context. Please don't remove comments. (I'm trying to ask nicely. Some others here take that kind of thing very personally..)</p>
<p><a href="/questions/223277-Why-Is-This-Happening-In-Maple#comment243572">@mapleatha</a> You have used the infix || elsewhere, in examples where it acts the same as `cat`. You used it for concatenation.</p>
<p>In your other, earlier Question you also had a rational value. I asked in my Answer there whether you needed that to be typeset (pretty-printed) in 2-D Math, rather that the as like "1/2" in 1-D text. You didn't confirm there. And now here you suddenly say that aspect is key.</p>
<p>It's not helpful if you don't give a complete description of what your trying to accomplish, at the start.</p>
<p>I'm not trying to berate you. It's a very common situation on Mapleprimes. People ask about a technical difficulty in an approach they've decided is good for some goal, without telling us all the requirements. Then there's a big circus as we try and dig down to get the true requirements out of them, so that we could suggest a quite different but better overall approach.</p>
<p>This current Question has turned out to be simply a duplicate of another two Questions asked by you, asked close together. Please don't submit three duplicates like that because it splits the value, confuses readers, and separates detail unnecessarily. Please just ask followups details/comments/subcases to Replies/Comments on the original.</p>
<p>You have deleted a comment to which I had responded above. Now my response looks out of context. Please don't remove comments. (I'm trying to ask nicely. Some others here take that kind of thing very personally..)</p>
243577Sat, 18 Nov 2017 16:05:49 Zaceracer