1) sin(3x-x) = 1 sin 2x = 1 2x = п/2 + 2пL x = п/4 + пL; 2)cosx = t; 2t^2 + 5t - 3 = 0; D = 49; t1 = -3 - не подх.; t2 = 0.5; cosx = 0.5; x = +- п/3 + 2пk;