Запишите в виде произведения sin19°+sin17°+sin15°.

\[\sin{19{^\circ}} + \sin{17{^\circ}} + \sin{15{^\circ}} =\]

\[= 2\sin\frac{34{^\circ}}{2} \cdot \cos\frac{4{^\circ}}{2} + \sin{17{^\circ}} =\]

\[= 2\sin{17{^\circ}} \cdot \cos{2{^\circ}} + \sin{17{^\circ}} =\]

\[= 2\sin{17{^\circ}}\left( \cos{2{^\circ}} + \frac{1}{2} \right) =\]

\[= 2\sin{17{^\circ}}\left( \cos{2{^\circ}} + \cos{60{^\circ}} \right) =\]

\[= 2\sin{17{^\circ}} \cdot 2\cos\frac{62{^\circ}}{2} \cdot \cos\frac{58{^\circ}}{2} =\]

\[= 4\sin{17{^\circ}} \cdot \cos{31{^\circ}} \cdot \cos{29{^\circ}}\]