posted by Derek .
If y= (x^2+20)/(x-4) Find all critical Numbers.
After get f' i got the answer -5/4. What did i do wrong or is that the critical number?
critical number: where y'=0 or y' undefined.
Anyway, y' = (x^2-8x-20)/(x-4)^2
y'=0 when x = -2,10
y' undefined when x = 4
how did you come up with -5/4 ?