Word problem, stuck at part a. (doh) I know that R=price*quantity, but i'm not sure how to set this one up and what to get the derivative of.

demand function for corn:

p=6,570,000/q^1.3

q is the number of bushels of corn that could be sold at p dollars per bushel in one year. Assume that at least 10,000 bushels must be sold each year.

a) How much should farmers charge per bushel to maximize annual revenue?

b) how much corn can farmers sell each year at that price?

c) what is the farmers' resulting revenue?