Hello.

I'd like to plot two coupled functions x=x(t) and y=y(t) given by expression R0 and R1 (see below) for the interval t=0.001..0.999 and then after that extract tha data from the graphs for functions x(t) and y(t).

How can I do that in easiest way?

I will appreciate you.

Hello everybody.

I'd like to share an observation about the integration of the Jacobi elliptic functions, in particularly the elliptic sine sn(x,k).

It's correct answer. But when I make the integration of the expression

according to the Handbook of Elliptic Integrals for Engineers and Scientists we have slightly another result

What is the difference?

Regarding my recent question http://www.mapleprimes.com/questions/221909-How-To-Extract-Data-From-Implicit-Function I would like to share an interesting observation. Here the code of the program:

restart;
R0 := ln(y)+Re(Psi(1/2+(2*(p^2+(1/2)*sqrt(2*I+4*ksi_fs^2*p^2)*tanh(sqrt(2*I+4*ksi_fs^2*p^2)*x)/(tau+0.5e-2*a)))/y))+gamma+2*ln(2)
tau:= 10.000:ksi_fs:=10:p:=0.037:
R0p:= unapply(R0, [a,x]):
R0f:= proc(a,x)
local r:= fsolve(R0p(a,x), y= 0..1);
   `if`(r::float, r, Float(undefined))
end proc:
M:= Matrix(
   (100,100),
   (i,j)-> R0f(i, 1 + (j-1)*(0.5-0)/(100-1)),
   datatype= float[8]
);

After approximately 2 hours of calculations I get a message window

But I repeat this calculations on another computer with the same Windows 7 64 bit and Maple 17 I don't get such error and I obtain desired data.

So can Maple be sensitive to the hardware? 

I plotted number of functions y=y(x) with different parameter aa for given value of tau (see the code below) 

restart;
R0:=gamma+2*ln(2)+Re(Psi(1/2+(1+I)*tanh((1+I)*x)/((tau+0.25e-1*a)*y)))+ln(y);
tau := 9.975;
with(plots);
implicitplot({seq(R0, a = 1 .. 50)}, x = 0 .. 5, y = 0 .. 1, numpoints = 1000);

Thanks in a advance.