Evaluate: `int_0^(pi//4)"log"(1+"t a n x")dx`

Explanation

To evaluate the integral \( I = \int_0^{\frac{\pi}{4}} \log(1 + \tan x) \, dx \), we can use a property of definite integrals.

### Step 1: Set Up the Integral
Let:
\[ I = \int_0^{\frac{\pi}{4}} \log(1 + \tan x) \, dx \]

...