а) ctg(pi/2+Y) = 1/tan(pi/2+Y) = 1/0 = undefined
б) tg(3pi/2-Y) = tan(3pi/2-Y) = tan(3pi/2) * tan(Y) = undefined
в) cos(180°+B) = cos(180°) cos(B) - sin(180°) sin(B) = -1 cos(B) - 0 sin(B) = -cos(B)
г) sin(90°-U) = sin(90°) cos(U) - cos(90°) sin(U) = 1 cos(U) - 0 sin(U) = cos(U)
а) ctg(pi/2+Y) = 1/tan(pi/2+Y) = 1/0 = undefined
б) tg(3pi/2-Y) = tan(3pi/2-Y) = tan(3pi/2) * tan(Y) = undefined
в) cos(180°+B) = cos(180°) cos(B) - sin(180°) sin(B) = -1 cos(B) - 0 sin(B) = -cos(B)
г) sin(90°-U) = sin(90°) cos(U) - cos(90°) sin(U) = 1 cos(U) - 0 sin(U) = cos(U)