What's wrong with Лобачевский function?
I tried to plot the following function $$Л(\theta) = -\int_0^\theta \log |2 \sin(u)| du$$ (called the Lobatchevski function). So I started with
sage: theta, u = var('theta', 'u') sage: assume(0 < theta < pi) sage: assume(theta, 'real') sage: el(theta) = - integral(log(abs(2*sin(u))), u, 0, theta)
The last command just asks maxima. Maxima starts computing (one CPUS is running 100%) but never stops.