17. \(4\) \(\sin \frac{\pi}{3} + \cos(-\frac{\pi}{2})\)

\(\sin \frac{\pi}{3} = \frac{\sqrt{3}}{2}\), \(\cos(-\frac{\pi}{2}) = 0\), поэтому \(\sin \frac{\pi}{3} + \cos(-\frac{\pi}{2}) = \frac{\sqrt{3}}{2} + 0 = \frac{\sqrt{3}}{2}\).