Answers
Located In The Following Attachments
High Hopes
Barry-
Answer:

Step-by-step explanation:
Given

Required
The phase
We have:

Rewrite as:

A cosine function is represented as:

Where:
Phase
By comparison:

Hence, the phase is: 
Answer: 0.3679
Step-by-step explanation:
The cumulative distribution function for exponential distribution is :-
, where
is the mean of the distribution.
Given : A mean length of waiting time equal
minutes
i.e. Mean number of calls answered in a minute 
Now, the proportion of callers is put on hold longer than 2.8 minutes is given by :_

Hence, the proportion of callers is put on hold longer than 2.8 minutes = 0.3679
7cos(x) + 1 = 6sec(x)
7cos(x) + 1 = 6/cos(x)
7cos^(x) + cos(x) = 6
7cos^(x) + cos(x) - 6 = 0
[7cos(x) - 6][cos(x) + 1] = 0
cos(x) = 6/7 , x = arccos(6/7) and
cos(x) = -1, x = 180
Point C is the answer I believe