5.
已知函数\(f(x)=\dfrac{\sqrt{3}}{2}\sin 2x-{{\cos }^{2}}x-\dfrac{1}{2}\),\((x\in R)\)
\((I)\)求函数\(f(x)\)的最小值和最小正周期;
\((II)\)设\(\Delta ABC\)的内角\(A,B,C\)的对边分别为\(a,b,c\),且\(c=\sqrt{3}\),\(f(C)=0\),若向量\( \overrightarrow{m}=\left(1,\sin A\right) \)与向量\( \overrightarrow{n}=\left(2,\sin B\right) \)共线,求\(a,b\)的值.