Question

ТЕРМІНОВО!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 1

Пошаговое объяснение:

$\cos(405) = \cos(360 + 45) = \cos(45) = \frac{ \sqrt{2} }{2}$

$\sin( \frac{11\pi}{6} ) = \sin(\pi + \pi \div 6) = - \sin(\pi \div 6) = - 1 \div 2$

sin70cos10 - sin10cos70 = sin(70-10) = sin60 =

$= \sqrt{3} \div 2$

$\cos(\pi \div 30) \cos(2\pi \div 15) - \sin(\pi \div 30) \sin(2\pi \div 15 )$

$= \cos( \frac{2\pi}{15} + \pi \div 30 ) = \cos( \frac{5\pi}{30} ) = \cos(\pi \div 6) = \sqrt{3} \div 2$