Alex Smith

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These are replies submitted by Alex Smith

I often have this same problem.

What I do is to paste first into a text editor, and then copy and paste into the application.

For me, pasting first into Winedt always works.

 

The problem is that eqs is already defined as a set, so there is a redundant pair of { } in solve.

 

Use this:

eqs:= {seq(seq(R[i,j] = A[i,j], i=1..2), j=1..2)};

solve(eqs, {a[1, 1], a[1, 2], a[2, 1], a[2, 2]});
 

 

 

The problem is that eqs is already defined as a set, so there is a redundant pair of { } in solve.

 

Use this:

eqs:= {seq(seq(R[i,j] = A[i,j], i=1..2), j=1..2)};

solve(eqs, {a[1, 1], a[1, 2], a[2, 1], a[2, 2]});
 

 

 

Your question seems ill posed.

Locally, there are infinitely many metrics for which R_{\mu\nu}=0.

Perhaps you want to compute Ricci curvature given the metric, instead of  "solving" for metrics with zero Ricci curvature?

Using MapleTA 4.0, I did not get the NULL pointer error that you described.

The mathml does look funny when c=-1 because x gets wrapped in unnecessary parentheses.

To avoid this, I suggest you modify your code as follows:

 

$a1=range(-5,5);
$c1=range(-5,5);
$c=if(($c1),($c1),1);
$a=if(($a1),($a1),1);
$n=range(3,5);
$q=maple("(($c)*x-($a))^($n)");
$P=maple("expand($q)");
$disp=maple("MathML[ExportPresentation]($q)");

It's never fun to type maple("MathML[ExportPresentation]($foo)") in place of mathml($foo), but the results are always much better. 

How did you enter the expression in Maple for the first c) image?

How did you enter the expression in Maple for the first c) image?

I found that with

f:=proc(x) if x>=0 and x<1 then 1 else 0 fi; end proc:
int(f,0..2) returns the error. 

However plot(f,0..2) works. 


I found that with

f:=proc(x) if x>=0 and x<1 then 1 else 0 fi; end proc:
int(f,0..2) returns the error. 

However plot(f,0..2) works. 


It seems that you should use LaTeX. I often help my colleagues in the Chemistry Department typeset papers using LaTeX, and it is an appropriate and extensible tool.

Maple fancies itself as a typesetting tool that equals the capacity of LaTeX, but this is hubris.

You entered

 

(1/40)*Pi*(Sum((1/40)*sin*i*Pi, i = 1 .. 10))

Instead you should enter

(1/40)*Pi*(Sum((1/40)*sin(i*Pi), i = 1 .. 10))

 

 

You entered

 

(1/40)*Pi*(Sum((1/40)*sin*i*Pi, i = 1 .. 10))

Instead you should enter

(1/40)*Pi*(Sum((1/40)*sin(i*Pi), i = 1 .. 10))

 

 

Here are the equations. I used Doug's method of digging to the alternate text which is a property of the graphic image.

 

eqa:= u[1]*u[2]*(B[1]-B[2]) = xi*(u[2]*E-u[2]*v[1]*B[1]-u[1]*E+u[1]*v[2]*B[2]);

eqb:= rho[1]*u[1]-rho[2]*u[2] = xi*(rho[1]*v[1]-rho[2]*v[2]);

eqc:=1/2*(2*rho[1]*u[1]^4*u[2]^2+2*p[1]*u[1]^2*u[2]^2-B[1]^2*u[1]^2*u[2]^2+u[2]^2*E^2-2*u[2]^2*E*v[1]*B[1]+u[2]^2*v[1]^2*B[1]^2-2*rho[2]*u[2]^4* u[1]^2-2*p[2]*u[1]^2*u[2]^2+B[2]^2*u[1]^2*u[2]^2-u[1]^2*E^2+2*u[1]^2*E*v[2]*B[2]-u[1]^2*v[2]^2*B[2]^2) = u[1]*u[2]*xi* (rho[1]*u[1]^2*v[1]*u[2]-B[1]*u[2]*E+B[1]^2*u[2]*v[1]-rho[2]*u[2]^2*v[2]*u[1]+B[2]*u[1]*E-B[2]^2*u[1]*v[2]);

 

eqd:=u[1]*u[2]*(rho[1]*u[1]^2*v[1]*u[2]-B[1]*u[2]*E+B[1]^2*u[2]*v[1]-rho[2]*u[2]^2*v[2]*u[1]+B[2]*u[1]*E-B[2]^2*u[1]*v[2]) = -(1/2)*xi* (-2*rho[1]*v[1]^2*u[1]^2*u[2]^2-2*p[1]*u[1]^2*u[2]^2-B[1]^2*u[1]^2*u[2]^2+u[2]^2*E^2-2*u[2]^2*E*v[1]*B[1]+u[2]^2*v[1]^2*B[1]^2+2*rho[2]*v[2]^2*u[1]^2*u[2]^2 +2*p[2]*u[1]^2*u[2]^2+B[2]^2*u[1]^2*u[2]^2-u[1]^2*E^2+2*u[1]^2*E*v[2]*B[2]-u[1]^2*v[2]^2*B[2]^2);

eqe:=u[2]*rho[1]*u[1]^2*v[1]^2*gamma-6*u[2]*E*v[1]*B[1]*gamma-u[1]*rho[2]*u[2]^2*v[2]^2*gamma+6*u[1]*E*v[2]*B[2]*gamma-u[2]*rho[1]*u[1]^4 +2*u[2]*E^2*gamma-4*u[2]*v[1]^2*B[1]^2+u[1]*rho[2]*u[2]^4-2*u[1]*E^2*gamma+4*u[1]*v[2]^2*B[2]^2-2*u[2]*E^2+2*u[1]*E^2+u[2]*rho[1]*u[1]^4*gamma- u[2]*rho[1]*u[1]^2*v[1]^2+2*u[2]*gamma*p[1]*u[1]^2+6*u[2]*E*v[1]*B[1]+4*u[2]*v[1]^2*B[1]^2*gamma-u[1]*rho[2]*u[2]^4*gamma+u[1]*rho[2]*u[2]^2*v[2]^2- 2*u[1]*gamma*p[2]*u[2]^2-6*u[1]*E*v[2]*B[2]-4*u[1]*v[2]^2*B[2]^2*gamma = u[1]*u[2]*xi*(v[1]*rho[1]*u[1]^2*gamma-v[1]*rho[1]*u[1]^2 +rho[1]*v[1]^3*gamma-rho[1]*v[1]^3+2*v[1]*gamma*p[1]+4*v[1]*B[1]^2*gamma-4*v[1]*B[1]^2-2*B[1]*E*gamma+2*B[1]*E-v[2]*rho[2]*u[2]^2*gamma +v[2]*rho[2]*u[2]^2-rho[2]*v[2]^3*gamma+rho[2]*v[2]^3-2*v[2]*gamma*p[2]-4*v[2]*B[2]^2*gamma+4*v[2]*B[2]^2+2*B[2]*E*gamma-2*B[2]*E);

In Maple 9.5, the following results:

solve({eqe, eqd, eqc, eqb, eqa}, {xi, u[1], v[1], p[1], B[1]});

 

{p[1] = p[1], u[1] = 0, xi = xi, v[1] = -rho[2]*(-xi*v[2]+u[2])/(xi*rho[1]),
B[1] = -xi*E*rho[1]/(rho[2]*(-xi*v[2]+u[2]))}

 

Subsequent to Maple 9.5, the solve command lost some functionality. It has still not been revived.

Listen to Jakubi. He is absolutely correct. It is hubris for Maple to think that quality typesetting can be attained by mouse clicking one's way through pallates.

  When `#mi( "V" )` ( with extra  spaces )  gives a diferent result from `#mi("V")`, you know you are in big trouble.

Earlier in the thread there is a reference to the "Typesetting [ Typeset ]" help page-note the redundant spaces.

I read it. Read it for yourself from a critical perspective. Does it really tell you anything useful at all? It includes one stupid example that  deals  with a subscript on a Bessel function.  The help page has some links, but by the time you follow them you feel like the poor fish named Dory in the movie "Finding Nemo." And from this we are supposed to infer the power and insightfullness of the Maple typesetting package?

Give us LaTeX support, otherwise the product will wither away.

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