Вычисли

а) \( \sin 30\degree + \sqrt{6}\cos 45\degree \sin 60\degree - \tg 30\degree \ctg 150\degree + \ctg 45\degree = \) [ ];

б) \(\cos \dfrac{\pi}{3} - \sqrt{2} \sin \dfrac{3\pi}{4}+\sqrt{3} \tg \cfrac{\pi}{3}= \) [ ].