Question

помогите решить,сижу не могу!!

Answer 1

1)

$sin(alpha)= frac{ sqrt{2} }{2} \ \ frac{ sqrt{2} }{2} = frac{pi}{4} = frac{3pi}{4} \ \ a= left { {{a= frac{pi}{4}+2pi n ,nin Z } atop { frac{3pi}{4}+2pi n , nin Z }} right.$

2)

$cos(alpha)=- frac{1}{2} \ \ - frac{1}{2}= frac{2pi}{3}= frac{4pi}{3} \ \ a= left { {{a= frac{2pi}{3}+2pi n,nin Z } atop {a= frac{4pi}{3}-2pi n,nin Z }} right.$

3)

$tg(alpha)=- frac{ sqrt{3} }{3} ,a neq frac{pi}{2}+pi n,nin Z \ \ a=arctg(- frac{ sqrt{3} }{3} )=- frac{pi}{6}+pi n,n in Z$

4)

$ctg(alpha)= sqrt{3} ,a neq kn,nin Z \ \ a=arcctg( sqrt{3})= frac{pi}{6}+pi n,nin Z$