display2d:false$
l:1$
g:9.80665$
ampl:1$
x(t):=ampl*sin(omega*t)$
eq:''(diff(x(t), t, 2)+g/l*sin(x(t)))$
assume(omega > 0)$
TIME:2*%pi/omega$
d:''(integrate(eq*eq, t, 0, TIME));
e:''(diff(d, omega));
solve(e, omega);
The integration already fails to yield something. What am I doing wrong? I'm still very uncertain about syntax....