Cos 7pi =Cospi =-1
Sin 7pi =Sin pi=0
Cos2.5pi=0
Sin2.5pi=1
Sin1/2pi+Sin3/2pi=0
Sinpi+Sin3/2pi=-1
Cos0+Cos3=?
5pi-Cos3pi=5pi+1
3Sin1/6pi+2Cos1/6pi-tg1/3pi=3/2+2кореньиз2-корень из3
5Sin1/4pi+3tg1/4pi-5Cos1/4pi-10ctg1/4pi=-7
(2tg1/6pi-tg1/3pi)/Cos1/6pi=(2/корень из3-корень из3)/корень из3/2=-2/3