Mark M. answered 09/08/23
Retired math prof. Calc 1, 2 and AP Calculus tutoring experience.
cos(2x) = 2cos2x - 1
So, 1 + cos(2x) = 2cos2x
The given limit is equivalent to limx→π/2 [ (1/2)(1 + cos(2x)) / ((1 + cos(2x))(2 + cos(2x)) ]
= (1/2) limx→π/2 [1 / (2 + cos(2x))] = 1/2 [ 1 / (2 + cosπ)] = 1/2