>>337
f(x)=2(sin(x))^2 - sin(x) cos(x)+ (cos(x))^2 = (sin(x))^2 - sin(x)cos(x) +1
2f(x) = 2(sin(x))^2 - 2sin(x)cos(x) +2 = - cos(2x) -sin(2x) + 3
= -(√2) sin(2x + (π/4)) + 3