Find the exact value of each of the following under the given conditions.\\
$\sin \alpha = \frac{3}{5}$, $0 < \alpha < \frac{\pi}{2}$; $\cos \beta = \frac{2\sqrt{53}}{53}$, $-\frac{\pi}{2} < \beta < 0$\\
(a) $\sin(\alpha + \beta)$ (b) $\cos(\alpha + \beta)$ (c) $\sin(\alpha - \beta)$ (d) $\tan(\alpha - \beta)$\\
(a) $\sin(\alpha + \beta) = $