Question

A manufacturer finds that the revenue generated by selling x gadgets is given by the function R(x)=320x-.2x^2, where the revenue r(x) is measurd in dollars. What is the maximum revenue?

a- $800
b- $1600
c- $128000
d- $384000
e- $256000

Answer 1

R' = 320 -4x That is the first derivative. The function will be a maximum when the first derivative is 0. So if 320-.4x = 0 x = 800 So now plug 800 into the original function and get 128,000

Answer 2

how did you get 800

Answer 3

?