Question

спростити вираз cos57°cos13° + sin57°sin13°​

Answer 1

Ответ:

$\cos( \alpha - \beta ) = \cos( \alpha ) \times \cos( \beta ) + \sin( \alpha ) \times \sin( \beta ) \\ \cos(57) \times \cos(13) + \sin(57) \times \sin(13) = \cos(57 - 13) = \cos(44)=0,7193$