74π/3 = 24 2/3 •π = 25π - 1/3π.
1) sin (25π - 1/3π) = sin (24π + π - 1/3π) = sin (π - 1/3π) = sin π/3 = √3/2.
2) cos (25π - 1/3π) = cos (π - 1/3π) = - cos π/3 = - 1/2.
