Curve sketching - Calculus: (x - 2) / (x^2 - 1)

Tinker

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Aug 14, 2008
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Having a bugger of a time with finding the critical pts (I find 2 yet only one graphs) and horizontal asymptote. And then there was the inflection pt . . .oh where?? Original equation: (x-2)/(x^2-1). Any and all tips and tricks are welcomed!
 
Re: Curve sketching - Calculus

If the power of the numerator is less than the power of the denominator, then the x-axis is the HA.

Graph it and you will see.

To check for inflection pts, find the 2nd derivative, set to 0 and solve for x.

The second derivative is \(\displaystyle \frac{2(x^{3}-6x^{2}+3x-2)}{(x^{2}-1)^{3}}\)

Set the numerator = 0 and solve for x. There will be 1 real solution.

For the critical points, use the first derivative.
 
Re: Curve sketching - Calculus

Sweet . . . but the HA is crossed when graphed?? And with the f"(x), I set f" to 0 =(x^3-6x^2+3x-2) . . . how does one solve for x? Thanks for your response and one other question if I may . . . how do you post in the nifty little functions (without having to use the ^ for exp)?
 
Re: Curve sketching - Calculus

That is LaTex. Click on 'quote' on my post to see what I typed to make it display that way.
 
Re: Curve sketching - Calculus

Tinker said:
Sweet . . . but the HA is crossed when graphed?? Yes that can happen - only once.

And with the f"(x), I set f" to 0 =(x^3-6x^2+3x-2) . . . how does one solve for x? Best way to estimate the root is to graph it. There are other numerical schemes - through which it can be shown that the root of the given cubic function is at x = 5.522333393


Thanks for your response and one other question if I may . . . how do you post in the nifty little functions (without having to use the ^ for exp)?
 
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