Question

sin68°×sin38°-sin 52°×cos 112°

Answer 1

sin52 = sin (0-38) = cos38 cos112 = cos (180-68) = - cos68. Торга sin68xsin38-sin52xcos112 = sin68sin38 + cos38cos68 = cos (68-38) = cos30 = (v3) / 2

Answer 2

Объяснение:

$\sin(52 ) = \cos(38) \\ \cos(112) = \cos(68) \\ \sin(68) \sin(38) + \cos(38) \cos(68) = \\ = \cos(68 - 38) = \\ = \cos(30) = \frac{ \sqrt{3} }{2}$