Question

ПОМОГИТЕ!!!! ОБЪЯСНИТЕ, КАК ЭТО РЕШАТЬ?!
sin $\frac{47\pi }{6}$
tg $\frac{25\pi }{4}$
ctg$\frac{27\pi }{4}$
cos$\frac{21\pi }{4}$

Answer 1

$Sin\frac{47\pi }{6} =Sin(8\pi-\frac{\pi }{6})=-Sin\frac{\pi }{6}=-0,5\\\\tg\frac{25\pi }{4}=tg(6\pi+\frac{\pi }{4})=tg\frac{\pi }{4}=1\\\\Ctg\frac{27\pi }{4}=Ctg(7\pi-\frac{\pi }{4})=-Ctg\frac{\pi }{4}=-1\\\\Cos\frac{21\pi }{4}=Cos(5\pi +\frac{\pi }{4}) =Cos(\pi+\frac{\pi }{4})=-Cos\frac{\pi }{4}=-\frac{\sqrt{2} }{2}$

Answer 2

1222234567890-=-09876543