\(\displaystyle \lim_{x\to \dfrac{\pi}{4}} \frac{8\sqrt{2}-(\cos x+\sin x)^{7}}{\sqrt{2}-\sqrt{2}\sin 2x} \) is equal to:
\( 14 \)
\( 7 \)
\( 14\sqrt{2} \)
\( 7\sqrt{2} \)