Answer:
I think it's A, y = 1/2 cos(x + π/4)
Answer:

Step-by-step explanation:
Let 1 unit be 0.4666...
16 units = 
15 units = 
15 units = 
1 unit = 
You can use google or safari... then click the first link (Type in your question)
The formula for the surface area of a cylinder is pi×2rh+2pi(r^2)
In this problem, r is 4 in and h is 16 in
Ratio of classes A, B, C = 4 : 6 : 5, respectively
4 + 6 + 5 = 15
So, class A represents 4/15 of the TOTAL population
Class B represents 6/15 of the TOTAL population
Class C represents 5/15 of the TOTAL population
So, weighted average of 3 groups combined = (4/15)(65) + (6/15)(80) + (5/15)(77)
= 260/15 + 480/15 + 385/15
= 1125/15
= 75
Answer: B