integral for an average cost function

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tmd1979

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An average cost function C(x)=(50000+75x)/x. How would we integrate when a=90 and b=100? Is it even possible?
 
\(\displaystyle \int_{90}^{100}\bigg[\frac{50,000+75x}{x}\bigg]dx \ = \ \int_{90}^{100}\bigg[\frac{50,000}{x}+75\bigg]dx\)
 
I understand that part. I used one of those online caclulators and it gave me 50000*log (x)+75x and another one gave me 6018.03... as the answer. I don't know how they got log in there and I don't know how they got 6018.03? Can you explain a little further, please? :?
 
tmd1979 said:
I understand that part. I used one of those online caclulators and it gave me 50000*log (x)+75x and another one gave me 6018.03... as the answer. I don't know how they got log in there and I don't know how they got 6018.03? Can you explain a little further, please? :?
Click to expand...

\(\displaystyle \int \frac{dx}{x} \ = \ ln(|x|) \ + \ C\)
 
I don't know how they got log in there and I don't know how they got 6018.03? Can you explain a little further, please?

\(\displaystyle Hey, \ tmd1979, \ you \ blew \ it \ on \ this \ one. \ You're \ fishing \ and \ I \ am \ not \ a \ fish.\)

\(\displaystyle In \ other \ words, \ if \ you \ don't \ know \ that \ \int\frac{1}{x}dx \ = \ ln|x|+C, \ you \ have \ no \ business\)

\(\displaystyle pestering \ this \ board \ on \ the \ machinations \ of \ The \ Calculus.\)
 
I had a momentary lapse of memory. I was not fishing!! As soon as I saw ln x, I remembered and was chastising myself for not remembering that in the first place. Sorry about that!
 
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