The problem ask to find the value of the cos(infinity) and the best answer, base on my further calculation and formulation that came up to a solution that leads me to an answer that the cos(infinity) is undefined but it has a range of (-1,1). I hope you are satisfied with my answer and feel free to ask for more
8.473 is the correct answer
The probability of 3 failures or less is about 0.83886, so that is the probability the machine will be working.
Area would be 4.52 A= pi x radius squared
Circumference would be 7.54 C= 2 pi radius. Hope that makes sense.