# Math Help - Help , please ! I don't know

1. ## Help , please ! I don't know

if f(x)= x/(x^2 +1)
(a) find f'(x) and f''(x)
Check to see that your answers to part (a) are reasonable by comparing the graphs of f, f' and f''

Help me !

2. Originally Posted by butbi9x
if f(x)= x/(x^2 +1)
(a) find f'(x) and f''(x)
Check to see that your answers to part (a) are reasonable by comparing the graphs of f, f' and f''

Help me !
Start by using the quotient rule to get f'(x).

To get f''(x), use the quotient rule to differentiate f'(x).

3. ## huhu

I don't understand

4. Originally Posted by butbi9x
I don't understand
Then go back to your textbook or class notes and revise the quotient rule and the chain rule. Then read my first post again.

5. if

$h(x) = \frac {f(x)}{g(x)}$

then

$h^\prime(x) = \frac {f^\prime(x)g(x) - g^\prime(x)f(x)}{g^2(x)}$