Problem on finding the second derivative.

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The discussion revolves around finding the second derivative of the function x/(x^2-4). The user initially calculated the first derivative as (-x^2-4)/(x^2-4)^2 but struggled with the second derivative, which they expressed in a complex form. Another participant provided a simplified version of the second derivative as (-6x/(x^2-4)^2) + (8x^3/(x^2-4)^3) and suggested rewriting the original function to avoid complications with fractions. The user ultimately confirmed they solved the problem and expressed gratitude for the advice. The conversation highlights the challenges of using the chain rule and the importance of simplification in derivative calculations.
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I have a problem on finding the second derivative for this function:

\frac {x}{x^2-4}

For the first derivative, I got:

\frac {-x^2-4}{(x^2-4)^2}

Now here is where I am stuck! So far for the second derivative, I got this (Please check!):

\frac {-2x(x^2-4)^2-4x(-x^2-4)(x^2-4)}{(x^2-4)^4}

I need this simplified! I know, it's an easy question. I may have lost my mind! :smile:
Also please show me the steps. Thanks!

BTW. I am new to this forum and just learned the latex system. It is very complicated. Took me a while just to write out the problems above. I guess I got to get used to it.
 
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First derivative is:

\frac{1}{x^2 -4} - \frac{2x^2}{(x^2-4)^2}

Second derivative is:
\frac{-6x}{(x^2-4)^2} + \frac{8x^3}{(x^2-4)^3}
 
it would be easier if you rewrite the original equation like this:
x(x^2 -4)^-1. So you don't need to deal with fractions
 
Aki said:
it would be easier if you rewrite the original equation like this:
x(x^2 -4)^-1. So you don't need to deal with fractions
Not necessarily. It is actually more complicated using the chain rule for this particular function. But either way is fine. I solved the problem already. Thanks for the advice though.

Here's a formula for finding quotient derivatives: (I'm sure you know it already)

Function: \frac {f(x)}{g(x)}

Formula: \frac{g(x)f'(x)-f(x)g'(x)}{[g(x)]^2}
 
Last edited:

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