Inputs & Production Relationships
(Exam Study Guide – Fully Explained)
1. What This Chapter Is About
This chapter studies how firms produce output using inputs and how they choose the best level of
production and resource use.
Main ideas:
Production and inputs
Costs of production
Profit maximisation
Input substitution (labour vs capital)
Product substitution (maize vs soybeans)
These ideas explain how firms make optimal production decisions.
2. Learning Outcomes (What You Must Know for
Exams)
From the lecture outcomes (page 4):
You must be able to:
1. Define profit and the profit function
2. Calculate total, average and marginal costs
3. Identify total revenue and total cost
4. Determine profit-maximising output
5. Analyse input substitution
6. Analyse product substitution
3. Conditions of Perfect Competition
According to the slide (page 5):
A perfectly competitive market has four key conditions.
1. Homogeneous products
All products are identical.
Example
Maize from one farmer is the same as maize from another farmer.
2. No barriers to entry
New firms can enter or exit the market freely.
3. Many sellers
Each firm is small relative to the market.
Therefore firms are price takers.
Meaning:
Firms cannot influence price — they accept the market price.
, 4. Perfect information
Everyone knows:
• prices
• quantities
• quality
4. Short Run vs Long Run
(Page 6)
Short Run
In the short run, at least one factor of production is fixed.
Example:
Land cannot change immediately.
Fixed Input
An input that cannot be changed in the short run.
Examples:
• buildings
• machinery
• land
Variable Input
Inputs that can change easily.
Examples:
• labour
• fertiliser
• fuel
Long Run
In the long run, all inputs are variable.
The firm can change:
• land
• labour
• capital
• technology
5. Total Cost of Production
(Page 8)
Total cost represents the cost of using all inputs.
Formula
TC = TFC + TVC
Fixed Costs (TFC)
Costs that do not change with output.
Examples:
• rent
• machinery
• insurance
Even if production = 0, fixed costs remain.
(Exam Study Guide – Fully Explained)
1. What This Chapter Is About
This chapter studies how firms produce output using inputs and how they choose the best level of
production and resource use.
Main ideas:
Production and inputs
Costs of production
Profit maximisation
Input substitution (labour vs capital)
Product substitution (maize vs soybeans)
These ideas explain how firms make optimal production decisions.
2. Learning Outcomes (What You Must Know for
Exams)
From the lecture outcomes (page 4):
You must be able to:
1. Define profit and the profit function
2. Calculate total, average and marginal costs
3. Identify total revenue and total cost
4. Determine profit-maximising output
5. Analyse input substitution
6. Analyse product substitution
3. Conditions of Perfect Competition
According to the slide (page 5):
A perfectly competitive market has four key conditions.
1. Homogeneous products
All products are identical.
Example
Maize from one farmer is the same as maize from another farmer.
2. No barriers to entry
New firms can enter or exit the market freely.
3. Many sellers
Each firm is small relative to the market.
Therefore firms are price takers.
Meaning:
Firms cannot influence price — they accept the market price.
, 4. Perfect information
Everyone knows:
• prices
• quantities
• quality
4. Short Run vs Long Run
(Page 6)
Short Run
In the short run, at least one factor of production is fixed.
Example:
Land cannot change immediately.
Fixed Input
An input that cannot be changed in the short run.
Examples:
• buildings
• machinery
• land
Variable Input
Inputs that can change easily.
Examples:
• labour
• fertiliser
• fuel
Long Run
In the long run, all inputs are variable.
The firm can change:
• land
• labour
• capital
• technology
5. Total Cost of Production
(Page 8)
Total cost represents the cost of using all inputs.
Formula
TC = TFC + TVC
Fixed Costs (TFC)
Costs that do not change with output.
Examples:
• rent
• machinery
• insurance
Even if production = 0, fixed costs remain.
