The lower limit is - 90 ° and the upper limit is the integral of 90 ° arctan (e ^ x) + arctan (e ^ - x) DX

The lower limit is - 90 ° and the upper limit is the integral of 90 ° arctan (e ^ x) + arctan (e ^ - x) DX

You draw a right triangle, and the right sides are e ^ x, 1
So, the two acute angles of this triangle are arctan (e ^ x) and arctan (e ^ - x)
So arctan (e ^ x) + arctan (e ^ - x) = 90 °, that is, π / 2, is a constant
So the integral result is π / 2 * x, which is brought into the upper and lower limits, and the final result is π ^ 2 / 2