A total revenue function is given by R(x) = 1000(x^2 - 0.1x)^1/2 , where R(x) is the total revenue, in thousands of dollars, from the sale of x items. Find the rate at which total revenue is changing when 20 items have been sold.

Answer 1

that would be dR/dx when x=20

R = 1000(x^2-.1x)^2
R' = 2000(x^2-.1x)(2x-.1)
R'(20) = 31,760,400

Answer 2

Calculate the amount of interest on a loan of $3,200 at 6% interest for 60 days using