Question

Вычислить: cos990-sin1470-ctg1125=

Answer 1

cos(270)-sin(30)-ctg(45)=-1,1

В ответе не уверен.

Answer 2

$cos990`=cos(4\pi+\frac{3\pi}{2}) = cos\frac{3\pi}{2}=0$

$sin1470` = sin(8\pi+\frac{\pi}{6})=sin\frac{\pi}{6}=\frac{1}{2}$ 

$ctg1125` = ctg(6\pi+\frac{\pi}{4}) = ctg\frac{\pi}{4} = 1$ 

 cos990-sin1470-ctg1125=0 - 1/2 - 1 = -3/2