We know that f (x) = cos x is a periodic function with period 2π.

∴ u (x) = cos² (x/2) is a periodic function with period π. So, we will draw the graph of u (x) = cos² (x/2) in the interval [0, π]. The values of u (x) = cos² (x/2) at various points in [0, π] are listed in the following table:

By plotting the above points, we obtain the required curve.