# TypeError: cannot solve differential equation

I am trying to use sagemath to solve a system of ordinary differential equation. However, I failed and got an TypeError (This returns the following error: TypeError: Computation failed since Maxima requested additional constraints; using the 'assume' command before evaluation may help). Here is my code for it. Could anyone help me with this? Thank you.

```
A=Matrix([[5/3, -4/3], [4/3, -5/3]])
B=Matrix([[2],[1]])
C=Matrix([-1,2])
D=Matrix([0])
t = var('t')
X=symb_mat(2,1,'X',t);
diffeqns = [eql == eqr \
for (eql,eqr) in zip(*[diff(X,t).list(),(A*X+B*u).list()])]
desolve_system(diffeqns,X.list(),ics=[0,1,2],ivar=t)
```

Would you mind typing your code in a way that makes it readable ?

Also, what is your

`symb_mat`

function ? I'm runningH. sapiens sapiens L.v 1.0, without divinatory processor nor telepathic interface...Thnks,

`calc314`

: now one can read the code. But that still doesn't tell us what`sumb_mat`

is supposed to do...I also see something called

`u`

used in the penultimate line, without a clue about what it could be.