1) sin(90-a)+cos(180+a)+tg(270+a)+ctg(360+a) = cos(a) - sin(a) + (-1) + 0 = cos(a) - sin(a) - 1.
2) sin^2(180-x) + sin(270-x) = 0 + (-1) = -1.
1) sin(90-a)+cos(180+a)+tg(270+a)+ctg(360+a) = cos(a) - sin(a) + (-1) + 0 = cos(a) - sin(a) - 1.
2) sin^2(180-x) + sin(270-x) = 0 + (-1) = -1.