Mathematics in Economics: Cost Function, Revenue Function and Profit Function

An important application of Mathematics is present in Economics through the Cost, Revenue and Profit Functions.
Cost Function
The cost function is related to the expenses made by a company, industry, store, in the production or acquisition of a product. The cost can have two parts: one fixed and one variable. We can represent a cost function using the following expression: C(x) = Cf + Cv, where Cf: fixed cost and Cv: variable cost
Recipe Function
The revenue function is linked to the gross sales of an entity, depending on the number of sales of a given product.
R(x) = px, where p: market price and x: number of goods sold.
Profit Function
The profit function refers to the companies' net profit, profit arising from the subtraction between the revenue function and the cost function.
L(x) = R(x) - C(x)

Example
A steel company manufactures pistons for automotive engine assemblers. The fixed monthly cost of R$ 950.00 includes electricity, water, taxes, salaries and so on. There is also a variable cost that depends on the number of pistons produced, the unit being R$ 41.00. Considering that the value of each piston on the market is equivalent to R$ 120.00, assemble the Cost, Revenue and Profit Functions. Calculate the net profit value on the sale of 1000 pistons and how many pieces, at a minimum, need to be sold in order to make a profit.


Total monthly cost function:
C(x) = 950 + 41x
Recipe Function
R(x) = 120x
Profit Function
L(x) = 120x - (950 + 41x)
Net profit in the production of 1000 pistons
L(1000) = 120*1000 – (950 + 41 * 1000)
L(1000) = 120,000 - (950 + 41000)
L(1000) = 120,000 - 950 - 41000
L(1000) = 120,000 - 41950
L(1000) = 78,050

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The net profit in the production of 1000 pistons will be R$ 78,050.00.
In order to make a profit, the revenue must be greater than the cost.
R(x) > C(x)
120x > 950 + 41x
120x – 41x > 950
79x > 950
x > 950 / 79
x > 12
To make a profit, you must sell over 12 pieces.

by Mark Noah
Graduated in Mathematics
Brazil School Team

Roles - Math - Brazil School

Would you like to reference this text in a school or academic work? Look:

SILVA, Marcos Noé Pedro da. "Mathematics in Economics: Cost Function, Revenue Function and Profit Function"; Brazil School. Available in: https://brasilescola.uol.com.br/matematica/matematica-na-economia-funcao-custo-funcao-receita-.htm. Accessed on June 28, 2021.

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