# What's wrong with Лобачевский function?

Hello,

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.

Vincent

Even that does not work:

This is actually pretty bizarre, and (sadly) yet

anothererror in Maxima's`abs_integrate`

. I'm getting really frustrated with that package about now, even though it adds a lot of awesome integrals. See http://trac.sagemath.org/ticket/17468