If *x* is the number of units of a product produced in some time interval, then:

total cost | = C(x) |

marginal cost | = C'(x) |

total revenue | = R(x) |

marginal revenue | = R'(x) |

total profit | = P(x) = R(x) - C(x) |

marginal profit | = P'(x) = R'(x) - C'(x) |

Drag the *x* slider to see how cost, revenue, and profit change with the number of units produced.

If *C(x)* is the total cost of producing *x* items, then the exact cost of producing the (*x* + 1)st item is:

C(x + 1) - C(x)The marginal cost function approximates the exact cost of producing the (

C'(x) ≈ C(x + 1) - C(x)

Similar statements can be made for total revenue functions and total profit functions.

If *x* is the number of units of a product produced in some time interval, then:

average cost | = C(x) | = C(x)/x |

marginal average cost | = C'(x) | = d/dx C(x) |

average revenue | = R(x) | = R(x)/x |

marginal average revenue | = R'(x) | = d/dx R(x) |

average profit | = P(x) | = P(x)/x |

marginal average profit | = P'(x) | = d/dx P(x) |