# Thread: Help deriving an equation

1. ## Help deriving an equation

I need to derive this function:

$\displaystyle \frac{2a}{1-x^2-a^2}$

$\displaystyle a$ is a constant

This is how i tried to solve it:

$\displaystyle 2a(1-x^2-a^2)^{-1}$

$\displaystyle \frac{4ax}{(1-x^2-a^2)^2}$

Thanks

2. Originally Posted by sebasto
I need to derive this function:

$\displaystyle \frac{2a}{1-x^2-a^2}$

$\displaystyle a$ is a constant

This is how i tried to solve it:

$\displaystyle 2a(1-x^2-a^2)^{-1}$

$\displaystyle \frac{4ax}{(1-x^2-a^2)^2}$

Thanks
I think what you mean is you want to DIFFERENTIATE (not derive) that EXPRESSION (not function!)

Remember is: If $\displaystyle y(x) = \frac{u(x)}{v(x)}$, then $\displaystyle y'(x) = \frac{v(x) u'(x) - u(x) v'(x)}{(v(x))^2}$

3. Well, it was a function from the beginning, but I just omitted the f(x) and f'(x)

Here we go again then..

I need to derive this function in relation to x:

$\displaystyle f(x)=\frac{2a}{1-x^2-a^2}$

$\displaystyle a$ is a constant

This is how i tried to solve it:

$\displaystyle f(x)=2a(1-x^2-a^2)^{-1}$

$\displaystyle f'(x)=\frac{4ax}{(1-x^2-a^2)^2}$

4. Originally Posted by sebasto
Well, it was a function from the beginning, but I just omitted the f(x) and f'(x)

Here we go again then..

I need to derive this function in relation to x:

$\displaystyle f(x)=\frac{2a}{1-x^2-a^2}$

$\displaystyle a$ is a constant

This is how i tried to solve it:

$\displaystyle f(x)=2a(1-x^2-a^2)^{-1}$

$\displaystyle f'(x)=\frac{4ax}{(1-x^2-a^2)^2}$