\[\boxed{\mathbf{1030.}}\]
\[1)\sin{(a + \beta}) +\]
\[+ \sin( - a) \bullet \cos( - \beta) =\]
\[= \sin a \bullet \cos\beta + \cos a \bullet \sin\beta +\]
\[+ \left( - \sin a \right) \bullet \cos\beta = \cos a \bullet \sin\beta.\]
\[2)\cos( - a) \bullet \sin( - \beta) -\]
\[- \sin(a - \beta) =\]
\[= \cos a \bullet \left( - \sin\beta \right) -\]
\[- \left( \sin a \bullet \cos\beta - \cos a \bullet \sin\beta \right) =\]
\[= - \cos a \bullet \sin\beta - \sin a \bullet \cos\beta +\]
\[+ \cos a \bullet \sin\beta = - \sin a \bullet \cos\beta\]
\[3)\cos\left( \frac{\pi}{2} - a \right) \bullet \sin\left( \frac{\pi}{2} - \beta \right) -\]
\[- \sin(a - \beta) =\]