maple fan

205 Reputation

14 Badges

13 years, 57 days

MaplePrimes Activity


These are questions asked by maple fan

restart;
#plot(exp('frem'(x+1,3)-1),x=-5..5,discont);
int(exp('frem'(x+1,3)-1),x=-5..5);
Error, (in int) wrong number (or type) of arguments: invalid options or option values passed to exact integration
evalf(Int(exp('frem'(x+1,3)-1),x=-5..5));
Error, (in evalf/int) when calling 'frem'. Received: 'invalid input: frem received x+1, which is not valid for its 1st argument, x'
sol1:=dsolve({diff(x(t), t)=eval(piecewise(0 <= t and t < 10/3, 60, 10/3 <= t and t < 13/3, 0),t='frem'(t,13/3)),x(0)=0},numeric,output=listprocedure);
sol2:=dsolve({diff(y(t),t)=eval(piecewise(0 <= t and t < 4, 50, 4 <= t and t < 5, 0),t='frem'(t,5)),y(0)=0},numeric,output=listprocedure);
#two commands above are well,but the below is not well.
sol:=dsolve({diff(x(t), t)=eval(piecewise(0 <= t and t < 10/3, 60, 10/3 <= t and t < 13/3, 0),t='frem'(t,13/3)),diff(y(t),t)=eval(piecewise(0 <= t and t < 4, 50, 4 <= t and t < 5, 0),t='frem'(t,5)),x(0)=0,y(0)=0},numeric,output=listprocedure);
Error, (in signum) invalid input: frem received t, which is not valid for its 1st argument, x
plots:-odeplot(sol,[[t,x(t)],[t,y(t),color=blue]],t=0..50,gridlines=true,thickness=2);
Error, (in plots/odeplot) input is not a valid dsolve/numeric solution.

any advice is appreciated.

I found this problem in a book about mathematica.
I want repeat it with maple.
But even Digits=1400, the exact value of s@x=70 is still different with the result(0.633319) on that book.
How to resolve this problem?
I want some help.

code:
restart;
Digits:=1400:
p:=convert(series(cos(x),x,201),polynom):
s:=add(op(i,p),i=[1,2,3,-1,-2,-3]);
add(evalf(coeff(p,x,i))*70^i,i=[200,198,196])+add(evalf(coeff(p,x,i))*70^i,i=[2])+add(evalf(coeff(p,x,i))*70^i,i=[4]);
#plot(s,x=0..40,view=[0..40,-2..2],numpoints=6000,gridlines,style=point);
simplify(eval(s,x=70));
evalf(%);

code:

restart;
convert([92*x/790+18*x*(1-y)/1000=0.125,ln(46.59/x)=1/1.5*(ln(0.553/y)+2.5*ln((1-y)/(1-0.553)))],rational);
fsolve(%);
plots:-implicitplot(%%,x=0..2,y=0..1,numpoints=1000,thickness=2,gridlines,color=[blue,red]);

question:

there is something missing with the red line. I can't find the intersect point on the figure.

Is there something wrong with implicitplot? 

the functions about vector field plot is so terrible,

is there any method to get it beautiful, like mathematica or matlab?

more options is needed for arrow's position, length, angle and color.

is there a plan for it?

And, the scalar field plot in 2d is better than vector field plot, but in 3d, isosurface plot are still need to be enhanced.

If possible, the plots in Plotting Guide are all need improve.

I found the page:http://12000.org/my_notes/rankTest/test.htm,

Comparing with MMa&Matlab, Maple is abit slow.

The author guess the reason is Intel MKL.

I searched the help page, http://www.maplesoft.com/support/help/Maple/view.aspx?path=copyright,

found this info:

Intel® MKL Copyright © 1999, 2000-2008 Intel Corporation. All rights reserved.

 Does this means the Intel MKL in maple is a 6 years old product?

Is this important?

I want to know.

1 2 3 4 5 6 7 Page 3 of 9