Hi, all. The problem is following. I have an ODE where right hand side is an integral function. For simplicity consider the following example:

with(DETools);

f:=q->int(exp(cos(s)), s=0..q);

DEplot({diff(x(t), t) = f(t)}, [x(t)], t = 0 .. 1, [[x(0) = 1]]);

this code doesn't work:

Error, (in DEtools/DEplot/CheckDE) extra unknowns found: s

Hi.

I can explain my question on the simplified example:

sol1 := dsolve({diff(x(t), t) = x(t), x(0) = 0.0}, numeric); 

func := q -> op(2, op(2, sol1(q))); 

dsolve({diff(z(t), t) = func(t) * z(t), z(0) = 0.1});

But i take a throw. It is clear, because, I try to call op(2, sol1(t)). Which way I whould use to solve my problem?

Hello.

I have following equation a = X.b, where a and b are n-dimension vectors, X is unknown nxn-dimension matrix. How can I find matrix X?