Question

Вычислите:

1) 4cos90° + 2cos180° - ctg 90°
2) cos0° - cos180° + sin 90°

Answer 1

$1) \ \ \ 4 \cos(90) + 2 \cos(180) - \cot(90) = 4 \times 0 + 2 \times ( - 1) - 0 = 0 - 2 - 0 = - 2.$

$2) \ \ \ \cos(0) - \cos(180) + \sin(90) = 1 - ( - 1) + 1 = 1 + 1 + 1 = 3.$

ответы:

1) -2.

2) 3.