In: Economics
How to draw the graph?
1. MPL=a+2bL-3cL^2
APL=a+bL-cL^2
2. MR=5-2Q
AR=5-Q
3.MC=6Q+7
AC=3Q+7+12/Q
I want detailed explanation??
thank you
Lets start with 2.
MR = 5 - 2Q
| 5 - 2Q | |
| Q | MR | 
| 1 | 3 | 
| 2 | 1 | 
| 3 | -1 | 

AR = 5 - Q
| 5 - Q | |
| Q | AR | 
| 1 | 4 | 
| 2 | 3 | 
| 3 | 2 | 
| 4 | 1 | 
| 5 | 0 | 

3.
MC = 6Q + 7
| 6Q + 7 | |
| Q | MC | 
| 1 | 13 | 
| 2 | 19 | 
| 3 | 25 | 
| 4 | 31 | 
| 5 | 37 | 

AC = 3Q + 7 + 12/Q
| 3Q + 7 + 12/Q | |
| Q | AC | 
| 1 | 22 | 
| 2 | 19 | 
| 3 | 20 | 
| 4 | 22 | 
| 5 | 24.4 | 

For 1st sub part
Lets find the output at which , MC = AC
6Q + 7 = 3Q + 7 + 12/Q
3Q = 12/Q
Q = 2
At Q=2, MC and AC both are 19.
Using the equations of MPL and APL now
Max value of APL will be when
differentiation of equation of APL = 0
d/dL(a+bL-cL^2) = 0
b - 2cL = 0
L = b/2c
At L = b/2c, we will get maximum value of APL.
At the same point APL and MPL will intersect as well.
Substituting L = b/2c in both equations of MPL and APL
APL = a + b(b/2c) - c(b/2c)^2 = a + b^2/2c - b^2/4c = a + b^2/4c
MPL = a + 2b(b/2c) - 3c(b/2c)^2 = a + b^2/c - 3b^2/4c = a + b^2/4c

In the above equation, it can be said that Max APL is at L2.
So, L2 = b/2c