



 
Hi Denise. I'll show you how this is done using different figures:
First, make P(x) depend on x without reference to R(x) and C(x).
The maximum value of P(x) is at a "critical point", so that means
So when we take the derivative of P, we get this:
Since this is the only critical point, this is our answer. So with my numbers, the maximum profit occurs when the number of units I've drawn a graph of P(x) so you can see what is happening: Now you try this method with your figures.
 


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 