Hi,

I found the plotted phase portrait strange and i verified it with phaseportrait

With plot :

Hi, i wouls lij=ke to see the consequences of damping on coupled oscillators.

I encounter no problem with

restart; m := 1; k1 := 1; k2 := 1; lambda := 0;

eq1 := m*diff(x1(t), `$`(t, 2)) = -k1*x1(t)+k2*(x2(t)-x1(t))-lambda*diff(x1(t), t);

eq2 := m*diff(x2(t), `$`(t, 2)) = -k2*(x2(t)-x1(t)); ICS := x1(0) = 1, x2(0) = 0, (D(x1))(0) = 0, (D(x2))(0) = 0; sol2 := dsolve({ICS, eq1, eq2}, {x1(t), x2(t)});

plot(eval(x2(t), sol2), t = 0 .. 20);

Hi,

Really, can't understand why there's a problem in the line desolve

restart;

eq1 := m*(diff(x1(t), t, t))-f = 0;

f := -k*x1(t)+k*(x2(t)-x1(t))-lambda*(diff(x1(t), t)) ;

g := -k*(x2(t)-x1(t)); eq2 := m*(diff(x2(t), t, t))-g = 0;

fcns := {x1(t), x2(t)};

ICS := {x1(0) = 1, x2(0) = 0, D(x1)(0) = 0, D(x2)(0) = 0};

sys := {eq1, eq2}; m := 1; k := 1; lambda := 1; sysdiff := sys union ICS;

Hi

1st, sorry, i did'nt find the "question" forum so i post here

2nd, difficulties in converting the maple code in text here

3rd : my problem of the day

retart :eq1 := m*(diff(x1(t), t, t))-f = 0; f := -k*x1(t)+k2*(x2(t)-x1(t))-lambda*(diff(x1(t), t));

eq2 := m*(diff(x1(t), t, t))-g = 0; g := -k2*(x2(t)-x1(t)); fcns := x1(t), x2(t);

ICS := {x1(0) = 1, x2(0) = 0, (D(x1))(0) = 0, (D(x2))(0) = 0};

sys := {eq1, eq2};...

hi,look at that. I obtain a curve. But when i do it again