In Maxima 5.20.1, the following evaluates to 0, which is correct, and the
simplest way of expressing the result.
(%i1) log(sqrt(2) - 1) + log(sqrt(2) + 1)$
(%i2) logcontract(%);
(%o2) 0
However, in Maxima 5.22.1 the same inputs leads to something quite different,
although mathematically it is is a correct result.
%i3) log(sqrt(2) - 1) + log(sqrt(2) + 1)$
(%i4) logcontract(%);
(%o4) log((sqrt(2) - 1) (sqrt(2) + 1))
Dave