We recognize that this has the form of a Riemann sum:
We identify
and
This gives us that
Now, notice that the function in question is f ( x ) = tan ( x ) {\displaystyle f(x)=\tan(x)} and so
and so we see that we can choose a = 0 {\displaystyle a=0} . This gives us that
Hence, the integral is
completing the question.