Solving the following differential equation:

function yprim = f(t, y)
    yprim(1) = y(2);
    yprim(2) = -4*y(1);
endfunction
t0 = 0;
tmax = 5;
t = t0:0.05:tmax;
y0 = 3;
yprim0 = 0;
y = ode([y0;yprim0], t0, t, f);
clf;
plot(t, y(1,:))

Read more in this tutorial: Scilab_beginners.pdf (4.62 MB)