Complex Numbers

$\frac{3}{2}$

$\cos ^2 \frac{\alpha}{2}+\cos ^2 \frac{\beta}{2}+\cos ^2 \frac{\gamma}{2}$

$3 \sin (\alpha+\beta+\gamma)$

$\cos (\alpha+\beta)+\cos (\beta+\gamma)+\cos (\gamma+\alpha)$