If \( f:\mathbb{R}\to\mathbb{R} \) be a continuous function satisfying \(\displaystyle \int_{0}^\dfrac{\pi}{2} f(\sin 2x)\sin x \, dx + \alpha \int_{0}^\dfrac{\pi}{4} f(\cos 2x)\cos x \, dx = 0 \), then the value of \( \alpha \) is:
\( \sqrt{2} \)
\( -\sqrt{3} \)
\( -\sqrt{2} \)
\( \sqrt{3} \)