http://img32.imageshack.us/img32/945/howx.jpg

Can anyone explain to me what happened here?

I understand that the 2 on the bottom is cause the denominator has to be the same, but I don't understand what happened on top.

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- Jul 21st 2009, 08:03 PMazurephantomAdding square roots (easy question)
http://img32.imageshack.us/img32/945/howx.jpg

Can anyone explain to me what happened here?

I understand that the 2 on the bottom is cause the denominator has to be the same, but I don't understand what happened on top. - Jul 21st 2009, 08:10 PMRapha
Hello.

$\displaystyle \sqrt{2} - 2 \sqrt{2} =1* \sqrt{2} - 2* \sqrt{2} = -1 \sqrt{2}$. because

$\displaystyle 1* \sqrt{2} - 2* \sqrt{2} = (1-2)*\sqrt{2} = (-1)*\sqrt{2}$

After that you can add the remaining '2' to $\displaystyle (-1)*\sqrt{2}$, because all these terms have the same denominator!

This leads to -$\displaystyle 1*\sqrt{2}+2 = -\sqrt{2}+2$ on the top

Yours

Rapha - Jul 21st 2009, 08:11 PMAlephZero
$\displaystyle \frac{\sqrt{2}}{2}-\frac{2\sqrt{2}}{2}+\frac{2}{2}$

$\displaystyle =\frac{\sqrt{2}-2\sqrt{2}+2}{2}=\frac{-\sqrt{2}+2}{2}.$