I have finals tomorrow. I just need help on these two questions. 

https://docs.google.com/document/d/1fmxz92NiiAX1CK6jEVC1khmE46kJN04rpwO9dim9xh4/edit?hl=en

Can you sanitize that post, maybe pasting it to notepad first, before posting it here? It's kind of unreadable with all the "italics", so I can't understand jack and can't help ya

first answer is 4050

x=90

the second the domaine is (3,infinite)

*it's any number that doesn't give a negative scareroot

what is v-1?? a derivative??

I have updated it, I posted it on Google docs. and the second one is not 3 to infinity. I tried that and got it wrong. I had to solve for x in order to find the domain and it worked. 

so the domain was 2.25, to infinity

And thanks for the first one. But how did you do it? I could barely see the graph on my calculator?

Thanks. I have updated it. 

2nd one, since it's a downward facing parabole, you need to find its critical point, which in turn will be the maximum. To find that, you need to know when the 1st derivative equals zero.

Hence

R(x) = 90x - 0.5 sq x

R'(x) = 90 - x = 0 -> x = 90

So he has to manufacture 90 units, to obtain the revenue, you only need to replace in R(x) -> $4050

my bad i thought you could only use ''whole'' numbers, for the first it's a simple derivative that you equal to 0 this will give you the critic numbers, usually you need to do a second derivative to find if your critic number is a minimum or a maximum but since you only get one answer 90 it's a min and a max at the same time

Yeah I understand now. What about the other question?

what is v-1?? a derivative??

i believe so, this was on the chapter dealing with inverse.