I solve a wave equation with Mathematica. The initial shift and speed I have already considered. However, I do not seem to be able to consider boundary conditions $ u (- pi, t) = u ( pi, t) = 0 $,

```
weqn = D(u(x, t), {t, 2}) == 4*D(u(x, t), {x, 2});
ic = {u(x, 0) == 0, Derivative(0, 1)(u)(x, 0) == (Sin(x))^2}
DSolveValue({weqn, ic}, u(x, t), {x, t})
Plot3D(%, {x, -Pi, Pi}, {t, 0, 4}, Mesh -> None)
```

I tried to write them everywhere. I always get another mistake.