\((1)\)已知向量\(\overrightarrow{a}=(2,4), \overrightarrow{b}=(1,1) \),若向量\(\vec{b}\bot (\vec{a}+\lambda \vec{b})\),则实数\(\lambda \)的值是_____________.
\((2)\)已知\(\sin \dfrac{\theta }{2}+\cos \dfrac{\theta }{2}=\dfrac{\sqrt{3}}{3}\), 则\(\cos 2\theta =\)_________.
\((3)\)已知向量\(\left| \overrightarrow{a}\right|=1,\left| \overrightarrow{b}\right|=2, \),\(\vec{a}\)与\(\vec{b}\)的夹角为\({{60}^{\circ }}\),则\(\vec{a}+\vec{b}\)在\(\vec{a}\)上的投影为_______________.
\((4)\sin {{50}^{0}}(1+\sqrt{3}\tan {{10}^{0}})\)的值为 ______________.