Try something like this: restart; mtest := [diff(m(t), t) = -43/25*exp(-8527.784461/(378.15+240*t) +19.03523317)*(m(t)-exp(-23300/(3143.93910+1995.360*t)+2.646139043)), m(0) = 1]; sol1 := dsolve(mtest,type=numeric, range=0..1,output=listprocedure); a := plots[odeplot](sol1,color=blue): mdot := eval(rhs(mtest[1]),sol1[2]); b := plot(mdot(t),t=0..1,color=red): plots[display]([a,b]); Is this what you are looking for? Regards, J. Tarr

You are not doing anything wrong: the equation mtest is a pair of first order odes, so dsolve,numeric returns a solution for m(t), but not its first derivative. If you want to plot diff(m(t),t), try solving the ode in p(t) and substituting the result into the ode in m(t). Hope this helps. J. Tarr

A plot can often help one understand a problem, so I suggest that you do something like this: restart: with(plots): x := 2*cos(t)+cos(2*t); y := 2*sin(t)-sin(2*t); X := r*cos(t); Y := r*sin(t); r := 1; circ := plot([X,Y,t=-Pi..Pi],color=black): z := plot([x,y,t=-Pi..Pi],color=red): display([circ,z],scaling=constrained); Try altering "r" and note the effect. Then solve like this: sol1 := solve({x=X , y=Y},t); sol2 := allvalues(sol1[1]); sols := sol1[2],sol2; Finally check that the solutions are correct by inserting them in the equations x = X and y = Y. Hope this helps. J. Tarr

Could you be a bit more specific please? Do you have the equation of a sphere and a list of points to plot? Or, do you need to produce a list of some points on the surface of a given sphere? Or, do you only have a list of points to which you want to fit a sphere before plotting the points and the sphere? J. Tarr

You might like to try this - it does what maximize should do. First download a copy of Robert Israel's Advisor and install it. Then restart; libname := "C:/Maths/Other/Advisor" , libname: # or whatever the path is to the Advisor files. for i to 20 do gmax( randpoly(x, degree=4), x=-5..5); od; Hope that you find Advisor useful. J. Tarr

The Optimization package made it much easier to find minima and maxima. Before that, Professor Robert Israel produced two procedures gmin and gmax for use with Maple V R5 and Maple 6, which seem to work with Maple 10. They produce min/max and location in floating point and were part of his Maple Advisor Package. I believe that someone has updated the package and it is available for download. Hope this helps. J. Tarr

In similar circumstances I have found it useful to split the worksheet into two parts, save the results to another file and then read these results into “part two” in a new worksheet. Hope that helps. J. Tarr

With anything other than a small matrix, symbolic eigenvalues and eigenvectors become an unreadable mess. So, is it essential to obtain symbolic eigenvectors from this 7 x 7 matrix? If you can use numerical values, Maple can easily produce the eigenvectors. With a bit of tidying, the result is more or less readable, as you will see from the worksheet linked below, in which I gave your symbols some arbitrary values. Hope this helps. J. Tarr View 724_Eigenvectors 7 x 7.mw on MapleNet or Download 724_Eigenvectors 7 x 7.mw
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It seems that verify needs some spoon-feeding. For example: a:={exp(I*x)=0, x^2-x}: b:={cos(x)+I*sin(x)=0, x*(x-1)}: verify(a, b, 'set(testeq)'); false restart; a:={exp(I*x)=0, x^2-x}: b:={convert(cos(x)+I*sin(x),exp)=0, expand(x*(x-1))}: verify(a, b,verify(a, b, 'set')); true Hope this helps. J. Tarr

Sorry - I assumed that you had Maple 10. It's a big improvement on 7. In my simplified example, the constraints on the fly were that its coordinates were bounded by a cube of side 5, as in your plot, and the spider was constrained to one place on the floor, again, as in your plot. These could be altered to suit your requirements, but without the Optimization package that's not much help. I am not sure how you should proceed using Maple 7, but perhaps ?linalg[norm] and linalg[grad] will give you a pointer. Good luck, J. Tarr

The min(seq(cd[i], i=1..12)) command causes the error message. If you don't mind a change of method, try something like this: restart; spider := ; fly := ; dist := fly - spider; dist := VectorCalculus:-Norm(%); fconstrain := {0<=fx,fx<=5,0<=fy,fy<=5,0<=fz,fz<=5}; sconstrain := {sx=2.5,sy=2.5,sz=0}; Optimization:-Maximize(dist,fconstrain union sconstrain); Hope this helps J. Tarr

The first two equations are too long to fit the posting space and disappear off the right side. Please upload your worksheet - see "Upload/Use File or Worksheet | Help", or split the two equations at a convenient addition, say, just before the last term. Someone should then be able to help you. Good luck, J. Tarr

The subject matter is well concealed in the help files. But take a look at Examples,LinearAlgebraMigration. Hope this helps, J. Tarr

If you had used worksheet mode instead of document mode, Edit>Find/Replace would have found all occurrences of II. Similarly, only one pair of single quotes would have been necessary to delay evaluation of the lhs of the last equation. Hope this helps. J. Tarr

Please see ?dsolve,numeric,IVP and ?dsolve,maxfun. Does the worksheet linked below do what you are looking for? I hope it helps. J.Tarr View 724_dsolve,numeric,IVP.mw on MapleNet or Download 724_dsolve,numeric,IVP.mw
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