Найдите значение:

а) sin 2,5pi; б) cos (-9pi/2) ; в) tg 13pi/6;

г) sin (-9pi/2) ; д) ctg 13pi/3; е) tg (-17pi/4)

А) Sin2,5π = Sin (2π + 0,5π) = Sin0,5π = 1

б) Cos (-9π / 2) = Cos9π/2 = Cos (4π + 0,5π) = Cos0,5π = 0

в) tg13π/6 = tg (2π + π/6) = tg π/6 = √3/3

г) Sin (-9π/2) = - Sin9π/2 = - Sin (4π + 0,5π) = - Sin0,5π = - 1

д) Ctg13π/3 = Ctg (4π + π/3) = Ctgπ/3 = √3/3

e) tg (-17π/4) = - tg17π/4 = - tg (4π + π/4) = - tg π/4 = - 1