25 ! cos(50град)+sin(160град)-cos(10град) - вопрос №7138556255016010 от DOMINOSHKAWWWRU 17.06.2020 00:32

Question

Математика: 25 ! cos(50град)+sin(160град)-cos(10град)

DOMINOSHKAWWWRU · Answer

сos 50°+ sin 160° - cos10° = сos 50°+ sin (180°- 20°) - cos 10° =
=(сos 50°- cos 10°) + sin (180°- 20°) =
= - 2 sin20° · sin30° + sin20° =
= sin20°(- 2 sin30° + 1) =
= sin20°(- 2 · 1/2 + 1) =
= sin20°(- 1 + 1) =
= sin20° · 0 = 0
ответ: 0