- #1
Larsani
- 9
- 0
Homework Statement
Find the inflection points and use second derivative test to determine where the function is concave up or down
Homework Equations
f(x) = (x - 1)/(x2 - 4)
The Attempt at a Solution
f'(x) = (-x2 + 2x - 4) / (x2 - 4)2
f''(x) = 2x3 - 6x2 +24x -8 / (x2-4)4
This is where I am stuck. I can't solve the numerator set to 0. You can factor out the 2 and that's about it. Cubic that I can't solve. I'm looking at:
x(x2 - 3x +12) = 4
and thinking that maybe I can use the quadratic equation to find when that quadratic = 0 but I don't think that will help me.