# Thread: Need help with a maximum revenue problem

1. ## Need help with a maximum revenue problem

Find the number of units x that produces a maximum revenue R if R = 30x^2/3-2x.

IF I'm right, the first derivative is 2/3(30x)^(-1/3)-2, and the second derivative is -2/9(30x)^-4/3.

This is where I run into the issues because I'm not good at all at figuring out which of the numbers in the exponent is supposed to go to the denominator and also what root it's supposed to be. I haven't taken any math classes for nearly 8 years and then I jumped right into Survey of Calculus, which is essentially calculus for business, and I'm having a great deal of difficulty. I need assistance with this question as it's on a quiz that's due tomorrow so if any of you could offer some assistance I would greatly appreciate it!

2. Originally Posted by gtudor
I'm not good at all at figuring out which of the numbers in the exponent is supposed to go to the denominator and also what root it's supposed to be.
What does that even mean?!

1) Stop thinking like this. Really, just stop it.

2) Figure it out. It is likely that you have been told to find where the first derivative is zero. This is an excellent place to start finding minima and maxima.

3) No one should care where you put exponents. If you realy, REALLY hate negative exponents, move them. Perhaps it would be convenient to move negative exponents from the numberator to their corresponding positive exponents in the denominator. On the other hand, it may not be particularly convenient.

4) Did I mention that you should stop beating yourself up?

3. I'm not trying to beat myself up. I just don't get it, hence the reason for my post.

4. You seem to have responded to #1 and #4. You did not respond WELL. Denial is a hard thing.

You did not respond at all to #2 or #3.

Let's see what you get.