Evaluate each of the following integral: `int_0^(pi//4)tan^2x\ dx`

Explanation

`\tan ^{2} x=\sec ^{2} x-1`


`\Rightarrow \int_{0}^{\pi / 4}-1 d x+\int_{0}^{\pi / 4}(\sec ^{2} x) d x `



`=-\pi / 4+[\tan x\}_{0}^{\pi / 4} `


`=1-\pi / 4`