# Getting an error while trying to solve a third order DE

The question is:

Solve the follwing differential equation using sagemath:

x'''(t) − 2x''(t) + 5x(t) = 0, x(0) = 0, x'(0) = 0, x''(0) = 1

I tried using this code:

```
var('s, t')
x = function('x')(t)
de = diff(x, t, 3) - 2*diff(x, t, 2) + 5*diff(x, t) == 0
show(desolve(de, x, ics = [0, 0, 0, 1]))
```

I am getting this error:

```
TypeError: ECL says: Error executing code in Maxima: diff: second argument must be a variable; found _SAGE_VAR_t
```

What am I doing wrong?

I have also tried using desolve_laplace instead of desolve