f(x) = sqrt(3) cos2x - (1-cos(pi/2 + 2x)) + 1 = sqrt(3)cos2x -sin2x = 2sin(pi/3 - 2x)
x = 5pi/12
pi/3 - 2x = -pi/2
f(x)最小
递增区间5pi/12 < x < pi/2
f(x) = sqrt(3) cos2x - (1-cos(pi/2 + 2x)) + 1 = sqrt(3)cos2x -sin2x = 2sin(pi/3 - 2x)
x = 5pi/12
pi/3 - 2x = -pi/2
f(x)最小
递增区间5pi/12 < x < pi/2