Answer:
(a)
(b)P'(5)=-($4.54) Thousand
(c)P'(11)=-($2.10) Thousand
(d)The fifth Month
Step-by-step explanation:
Given the monthly profit model:

(a)We want to derive a model that gives the Marginal Profit, P' of the book.
We differentiate
using quotient rule.

Simplifying

We have derived a model for the marginal profit.
(b) After 5 months, at t=5
Marginal Profit=P'(5)


=-($4.54) Thousand of dollars
(c)Marginal Profit 11 Months after book release

=-($2.10) Thousand of dollars
(d) Since the marginal profit at t=5 is negative, after the 5th Month, the profit starts to experience a steady decrease.
1. √48 → √16 * √3 = 4√3
3. √12 → √4 * √3 = 2√3
7. √125 → √25 * √5 = 5√5
8. √20 → √4 * √5 = 2√5
9. √18 → √9 * √2 = 3√2
10. √32 → √16 * √2 = 4√2
11. √50 → √25 * √2 = 5√2
12. √27 → √9 * √3 = 3√3