\(\cos^2\left(\frac{x}{2}\right)=\dfrac{1+\cos x}{2}=\frac{3}{4}\)
\(\sin^2\left(\frac{x}{2}\right)=\dfrac{1-\cos x}{2}=\frac{1}{4}\)
Since \(x\) is in quadrant II, we know that \(\sin x > 0\) and \(\cos x < 0\), therefore \(\cos\left(\frac{x}{2}\right)=-\frac{\sqrt{3}}{2}\) and \(\sin\left(\frac{x}{2}\right)=\frac{1}{2}\).