Everybody remembers the cosine values $$\cos 0 = 1,\quad \cos(\pm\pi) = -1,\quad \cos(\pm2\pi) = 1,\quad \cos(\pm3\pi) = -1,\,\,...$$ The thing can be concisely expressed as the formula $$\cos{n\pi} = (-1)^n$$ for each integer $n$ . The values of sine at the same angles are simply 0.