Question

Знайти значення виразу Срочноо

Answer 1

$\frac{Cos(-\frac{13\pi }{3} )-Sin(-\frac{13\pi }{6})}{Ctg(-\frac{13\pi }{4})}=\frac{Cos\frac{13\pi }{3}+Sin\frac{13\pi }{6}}{-Ctg\frac{13\pi }{4}}=\\\\=\frac{Cos(4\pi+\frac{\pi}{3})+Sin(2\pi+\frac{\pi }{6})}{-Ctg(3\pi+\frac{\pi }{4})}=\frac{Cos\frac{\pi }{3} +Sin\frac{\pi }{6}}{-Ctg\frac{\pi }{4}}=-\frac{\frac{1}{2}+\frac{1}{2}}{1}=\boxed{-1}$