I assume that 6 and 60 are in degrees and not radians.
1. Cos Ф = adjacent side / hypotenuse in a right angle triangle = a/b.
When angle Ф = 0, a = b and as Ф increases 'a' remains same and b, the hypotenuse increases. So cos Ф decreases continuously as Ф increases till Ф = 90 deg.
2. The graph of cos Ф shows the wave like property of Cos and it decreases between Ф = 0 to Ф = 180 deg.
So COS 6 is greater than COS 60.