Dear all,

I have one quetion. I have written maple code based on Dr.Robert J. Lopez's one.

Here is my code.

> q1 := diff(x(t),t) = -a*x(t)*y(t) + b*z(t);

q2 := diff(y(t),t) = -a*x(t)*y(t) + b*z(t);

q3 := diff(z(t),t) =  a*x(t)*y(t) - b*z(t);

q4:=k(t)=x(t)*y(t)/z(t);

ic := x(0)=10,y(0)=10,z(0)=0;

C := < I put Experimental data….>:

> SS := proc(a,b)

local F, V;

if not type([a,b],['numeric','numeric']) then return 'SS'(a,b);

elif a<0 or b<0 then return 1e100;

end if;

F := dsolve(eval({q1,q2,q3,q4,ic},{:-a=a,:-b=b}),[x(t),y(t),z(t),k(t)],numeric, output=Array([seq(k,k=0..N)]));

V := convert(Column(F[2,1],5),Vector);

Norm(V-C,2);

end proc:

 I just put one more equation -eqn4. it is not differential equation.

I currently have error massage from maple. Could you let me know how I solve the equations in this case?

Thanks.

Dear all

I have one question regarding to dsolve.

Let say I have simple function,

 dx/dt =A+Bx

 dy/dt =A'+B'y

when I want to get graph of x as function of time or y as fuction of time, I can use 'dsolve'

For example, I can put "" soln:=dsolve ((ABOVE EQUATION, ICs),numerical,implicit=true) ""

                                     plot(soln,x(t) or y(t))

Also, When I want to get x value or y value as function of time, I can use soln(t), t could be whatever I want.

However, I want to get or draw graph " t " as function of x or function of y. For example, I want to know  t value when x=3 or I want to know t value when y=5. Above equations are simple, so I can calculate by hand. but I want to know which command I need or which ways are in MAPLE to get the value.

Thanks.

Hi I have one question.

I want to draw y=sin(t). x-axis is time and y-axis from 0 to 1.

I want to convert x-axis into cycle number. For example, in case of y= sin(t), one cycle is 2phi.

--------------------------------------------------------x-aixs                ->  -----------------------------------------------------x-aixs

1                    2phi                       4phi               (time)                                         1                         2           (cycle number)

It is simple function, so if I put t/2Phi instead of t, I can get a graph with cycle number. But Do you know other ways to convert that?