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Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions D P Q
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Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

Dec 22, 2015

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Page 1: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

Lectures in Microeconomics-Charles W. Upton

The Mathematics of Demand Functions

D

P

Q

Page 2: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Demand Functions In Different Forms

• Graphs of quantity demanded against price

D

P

Q

Page 3: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Demand Functions In Different Forms

• Graphs of quantity demanded against price– They need not be

straight lines

D

P

Q

Page 4: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Demand Functions In Different Forms

• Tables Price Quantity

$0.40 100

$0.50 90

$0.60 80

Page 5: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Demand Functions In Different Forms

• Mathematical equations

Q=100-2P

Page 6: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Demand Functions In Different Forms

• Mathematical equations– Linear or Non

Linear

Q=100-2P

Q=10P-2

Page 7: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Indirect demand functions

• Gives price as a function of quantity, not the other way around.

• We can always restate indirect demand functions as direct demand functions and vice versa.

Page 8: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

A Graphical Interpretation

• Knowing price we know quantity demanded.

D

P

Q

Page 9: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

A Graphical Interpretation

• It also works the other way.

D

P

Q

Page 10: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Ditto with Tables

Price Quantity

$0.40 100

$0.50 90

$0.60 80

Page 11: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

An Example

Q = 100 – 2P

Page 12: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

An Example

Q = 100 – 2P

2P + Q = 100 – 2P +2P

Page 13: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

An Example

Q = 100 – 2P

2P + Q = 100 – 2P +2P

2P + Q = 100

Page 14: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

An Example

2P + Q = 100

2P + Q – Q = 100 – Q

2P = 100 – Q

Page 15: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

An Example

2P = 100 – Q

(1/2)[2P] = (1/2)[100-Q]

P = 50 – (1/2)Q

Page 16: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

A Second Example

P = 50 – (1/2)Q

Page 17: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

A Second Example

P = 50 – (1/2)Q

2P = 2[50-(1/2)Q]

2P = 100 – Q

Page 18: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

A Second Example

2P = 100 – Q

Q + 2P = 100 – Q + Q

Q + 2P = 100

Page 19: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

A Second Example

Q + 2P = 100 – Q + Q

Q + 2P = 100

Q + 2P – 2P = 100 –2P

Q = 100 – 2P

Page 20: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Some Assignments

P = 12 – 3Q

Q = 100 – 10P

Page 21: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

Some Assignments

P = 12 – 3Q

Q = 100 – 10P

Q = 4 – (1/3)P

P = 10 – 0.1Q

Page 22: Lectures in Microeconomics-Charles W. Upton The Mathematics of Demand Functions.

The Mathematics of Demand Functions

End

©2004 Charles W. Upton