# Cost

A cost function indicates to the monopolist how much it costs to produce a given quantity.

## Example

To produce a quantity Q of lemonade, it costs Zoe $$C \left( Q \right) = 2Q$$ If she makes 2 liters of lemonade, it will cost her $$C \left( 2 \right) = 2 \times 2 = 4$$

### Question

Zoe's cost function is $$C \left( Q \right) = 6 Q + 70$$ How much does it cost to produce 3 liters of lemonade?

Plug Q = 3 into C \left( Q \right) = 6 Q + 70 \begin{align*} C \left( Q \right) &= 6 Q + 70 \\ &= 6 \times 3 + 70 \\ &= 18 + 70 \\ &= 88 \end{align*}