Question

Обчислити:

a) 8 cos 90° - 7 cos 180° + 3 sin 270°

b) sin π + cos π + tg π

c) sinπ/4 · tg π/2

Answer 1

$\displaystyle\bf\\1)\\\\8Cos90^\circ-7Cos180^\circ+3Sin270^\circ=8\cdot 0-7\cdot(-1)+3\cdot(-1)=\\\\\\=0+7-3=4\\\\2)\\\\Sin\pi +Cos\pi +tg\pi =0-1+0=-1\\\\3)\\\\Sin\frac{\pi }{4} \cdot tg\frac{\pi }{2} =\frac{\sqrt{2} }{2} \cdot ...$

tg π\2  -  не существует