Posted by Anonymous on .
Let f be defined as follows.
y = f(x) = x^2  4 x
(a) Find the average rate of change of y with respect to x in the following intervals.
from x = 5 to x = 5.5
For some reason I keep getting this wrong. The way I did it was: f((5.5)f(5))/(x2x1)= 225/5.55=34 This is wrong, could someone show me what I'm doing wrong?

Calculus 
Reiny,
for f(5.5) I got 8.25
http://www.google.ca/search?hl=en&q=5.5%5E2++4*5.5&btnG=Search&aq=f&aqi=&aql=&oq= 
Calculus 
MathMate,
You probably had a typo in the formula, which should read:
( f(x2)f(x1) ) / ( x2x1 )
For the interval [5,5.5]
(f(5.5)f(5))/(5.55)
=(8.255)/(5.55)
=6.5
Post again if you still have problems.