Hi,

i want to use "dsolve({ODE1, IC1, IC2},numeric)" in a procedure. But it has some problems with the curly brace. Is there a special command to replace the curly brace?

Thanks

Hey,

i have 2 differential equations and want to solve the first one when x is positive and the second when x ist negativ. For this problem i wrote the follwing procedure. But when i try i have the posted error. Has someone a good idea to help me?

Thanks a lot

> DGL3 := 10*(D(D(x)))(t) = x(t);

> DGL4 := 10*(D(D(x)))(t)+5000 = x(t);

Tsolver:=proc()
global DG1, DG2, func, var, var_min, var_max, x, Dx, N:

Hey there i try to solve this system of equations. It is required that the left side of the equation only take positive values. Has someone an idea to fix this solution or has maybe another idea to help me.

> m[1] := 30; c[1] := 48000; c[0] := 20000; d[1] := 21; d[0] := 70;

> DGL1 := m[1]*(D(D(x)))(t)+d[0]*(D(x))(t)+d[1]*(D(x))(t)+c[0]*x(t)+c[1]*x(t)+50000 = -(1/1000)*c[1]*S-(1/1000)*d[1]*DS*((1/60)*(2*Pi*250))-(1/1000)*m[1]*DDS*((1/60)*(2*Pi*250))^2;

Hey there,

i have a differential equation in the form below and the expression c1*x(t) should only be positive. Has someone an idea how to solve this problem?

Hey there,

i´ve a numerical solved differential equation and a "normal" equation. How can i calculate the differenz of both?

>S:=0.79*cos(t)+0.3*sin(t);

> DGL1 := 20*(D(D(x)))(t)+10*(D(x))(t)+2500*x(t)+300 = S;
> init := x(1.2) = 0, (D(x))(1.2) = 10.63081252;
> F := dsolve({DGL1, init}, numeric);
>U:=F-S;

> p1 := plot(U, [t, x(t)], 1.2 .. 2, numpoints = 200);
%;
Error, (in plot) two lists...