Maximizing Profit with Calculus: Understanding the Profit Formula

[xmf77]

Homework Statement

For a monopolist's product,

the demand equation is

p=30−2q

and the average-cost function is

c=2+40q.

Find the profit-maximizing price.

Relevant Equations

Calculus, maximizing, profit, price

I know the formula profit = (price-cost)quantity.
but when ı applied the numbers ı can not substitute them
profit = ((30-2q-2-(40/q))

but don't know what ı need to do ?
would appreciate any help given please.

 

[PeroK]

Homework Statement:: For a monopolist's product,

the demand equation is

p=30−2q

and the average-cost function is

c=2+40q.

Find the profit-maximizing price.
Relevant Equations:: Calculus, maximizing, profit, price

I know the formula profit = (price-cost)quantity.
but when ı applied the numbers ı can not substitute them
profit = ((30-2q-2-(40/q))

but don't know what ı need to do ?
would appreciate any help given please.

You need to express your profit equation in terms of price, not in terms of demand.

 

[xmf77]

İs there anyone?

 

[FactChecker]

Is 'q' quantity? Is 'p' price? Did you include the quantity multiplier in your substitution into the profit equation?