# Math Help - derrivative

1. ## derrivative

f(x)=x/[x+(c/x)]

2. Originally Posted by johntuan
f(x)=x/[x+(c/x)]

Is c a constant? If so

$\frac{x}{x + \frac{c}{x}} = \frac{x}{\frac{x^2+c}{x}}= \frac{x^2}{x^2+c}$

Take the derivative of that

$\frac{(2x)(x^2+c)~-~(2x)(x^2)}{(x^2+c)^2}$

Now just simplify

$\frac{2cx}{(x^2+c)^2}$

3. You can use the quotient rule, but I don't quite remember it, so I'll just give you the necessary information.
Top = x
Derivative of the top= 1
Bottom = (x + c/x)
Derivative of the bottom = 1 + -c/(x^2)

Assuming that c is a constant.

4. i'm not sure if c is a constant but the answer is f'(x)=2cx/(x^2+c)^2