Найти значение синуса и косинуса бетта, если 1)

$1) \ sin(3\pi) = sin(\pi + 2\pi) = sin(\pi) = 0\\\\ cos(3\pi) = cos(\pi + 2\pi) = cos(\pi) = -1\\\\ 2) \ sin(4\pi) = sin(2\pi + 2\pi) = sin(2\pi) = sin(0+2\pi) = sin(0) = 0\\\\ cos(4\pi) = cos(2\pi + 2\pi) = cos(2\pi) = cos(0+2\pi) = cos(0) = 1\\\\$

$3) \ sin(3.5\pi) = sin(1.5\pi + 2\pi) = sin(1.5\pi) =\\ sin(\frac{\pi}{2}+\pi) = -sin(\frac{\pi}{2}) = -1\\\\ cos(3.5\pi) = cos(1.5\pi + 2\pi) = cos(1.5\pi) =\\ cos(\frac{\pi}{2}+\pi) = -cos(\frac{\pi}{2}) = 0\\\\ 4) \ sin(2.5\pi) = sin(\frac{\pi}{2}+2\pi) = sin(\frac{\pi}{2}) = 1\\\\ cos(2.5\pi) = cos(\frac{\pi}{2}+2\pi) = cos(\frac{\pi}{2}) = 0$