Levels Tought:
Elementary,Middle School,High School,College,University,PHD
Teaching Since: | Apr 2017 |
Last Sign in: | 235 Weeks Ago, 3 Days Ago |
Questions Answered: | 12843 |
Tutorials Posted: | 12834 |
MBA, Ph.D in Management
Harvard university
Feb-1997 - Aug-2003
Professor
Strayer University
Jan-2007 - Present
f(x) = x3Â -3x2Â + 4 <------ is the model for revenue function and x represents years, y=f(x) represents revenue in thousands of dollars. Assume the model is valid for the years 0<x<5
Â
1.Find the rate of change of the revenue in year 3
[I don't see the 'average' word in here so I'm not sure if I have to find the Af(x) and then the Af'(x) or skip that all and calculate f'(x). I just did all of them.]
Â
1.0 - f'(x) = 3x2-6x
1.1 - Af(x) = f(x) / x --------------> x2Â - 3x + (4/x)
1.2 - Af'(x) = (fg' - gf')/(g2) ----> 2x - 3 - (4/x2)
Â
Find the rate of change of revenue in year 3
1.3 - f'(3) = 3(3)2Â - 6(3) = 27 - 18 = 9
1.4 - Af'(x) = 2(3)-3-(4/(3)2) = 6 - 3 - (4/9) = 2.555555555556
Â
2. In what years are the rates of change equal to 0?
2.0 - f'(x) =Â 3x2-6x
0 = 3x2-6x
6x = 3x2
6 = 3x
2 = x -------------> f'(2) = 3(2)2Â - 6(2) --------> f'(2) = 12 - 12 = 0
2.1 -Â Af'(x) = (fg' - gf')/(g2) ----> 2x - 3 - (4/x2)
0 = 2x - 3 - (4/x2)
3 = 2x - (4/x2)
3x = 2x2Â - 4 .......................stopping since it feels futile.
Â
3. Graph the revenue function and in what x interval is the revenue decreasing and in what interval is the revenue increasing?
Â
-----------