How do i find the dirivative of y=x-1/2x^2.

Thats. y=x - 1 divided by 2x to the power 2.

Any help would be greatful.

Thanks, James.

(where does the math notations everyone seems to use come from? )

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- Nov 9th 2007, 04:14 AMjames jarvisstruggling to find a dirivative
How do i find the dirivative of y=x-1/2x^2.

Thats. y=x - 1 divided by 2x to the power 2.

Any help would be greatful.

Thanks, James.

(where does the math notations everyone seems to use come from? ) - Nov 9th 2007, 04:26 AMKrizalid
Split the fraction in two pieces, then use the power rule for derivatives.

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LaTeX stuff can be found here. - Nov 9th 2007, 04:27 AMjanvdl
We use Latex. (I'll go search for the tutorial and then edit my post and paste it here okay?)

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

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

$\displaystyle = \frac{1}{4} - \frac{1}{2} x^{-1} + \frac{1}{4}x^{-2}$

$\displaystyle \frac{dy}{dx} = 0 + \frac{1}{2} x^{-2} - \frac{1}{2}x^{-3}$

$\displaystyle = \frac{1}{2x^2} - \frac{1}{2x^3}$

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EDIT: Krizalid gave you the link :D - Nov 9th 2007, 04:34 AMjames jarvis
Thanks for reply. Always makes sense when you see it! :)

- Nov 9th 2007, 04:35 AMjanvdl
- Nov 9th 2007, 06:49 AMjackddogHow to find derivative
Your question is not clear.

a) Is the 2x under the 1 only or under x as well?

b) Is it (2)(x^2) or is it (2x)^2. That is, is it just the x that is raised to power 2 or the 2x?

Tell me which is which and I will tell you......how - Nov 9th 2007, 06:51 AMjanvdl
- Nov 9th 2007, 02:08 PM2taall
I think you use the Quotient Rule.