The value of \( \tan^{-1}\!\left( \frac{\cos\!\left( \frac{15\pi}{4} \right)}{\sin\!\left( \frac{\pi}{4} \right)} - 1 \right) \) is equal to:
If \( \sin^{-1}\frac{\alpha}{17}\ + \cos^{-1}\frac{4}{5}\ - \tan^{-1}\frac{77}{36}\ = 0 ,\; 0<\alpha<13 \), then \( \sin^{-1}(\sin \alpha) + \cos^{-1}(\cos \alpha) \) is equal to:
\( \max\limits_{0 \le x \le \pi} \left\{ x - 2 \sin x \cos x + \dfrac{1}{3} \sin 3x \right\} = \)
