Question

Формулы приведения. sin 225 cos 210 tg210 ctg240

Answer 1

$1)Sin225^{0} =Sin(180^{0}+45^{0})=-Sin45^{0}=\boxed{-\frac{\sqrt{2} }{2}} \\\\2)Cos210^{0}=Cos(180^{0}+30^{0})=-Cos30^{0}=\boxed{-\frac{\sqrt{3} }{2}}\\\\3)tg210^{0} =tg(180^{0}+30^{0})=tg30^{0}=\boxed{\frac{\sqrt{3}}{3}}\\\\4)Ctg240^{0}=Ctg(180^{0}+60^{0})=Ctg60^{0}=\boxed{\frac{\sqrt{3} }{3}}$