Substituting <em>x</em> with <em>π</em>/2 - <em>x</em> gives the equivalent integral,
So if we let <em>J</em> denote the value of the integral, we have
Condensing the logarithms, we have
log(tan(<em>x</em>)) + log(cot(<em>x</em>)) = log(tan(<em>x</em>) cot(<em>x</em>)) = log(1) = 0
since cot(<em>x</em>) = 1/tan(<em>x</em>), which means
and so the original integral has a value of <em>J</em> = 0.
