The integral \(\displaystyle \int_{1/4}^{3/4} \, \cos\!\left( 2\cot^{-1}\!\sqrt{\frac{1-x}{1+x}} \right) \, dx \) is equal to
\( -{1}/{4} \)
\( -{1}/{2} \)
\( {1}/{2} \)
\( {1}/{4} \)