# simple equation

• Sep 17th 2011, 10:22 PM
planetdomi
simple equation
Im having difficulty understanding something simple:

Can someone show me how it is possible to get from

2a² = d²

to

d = a√2

many thanks
• Sep 17th 2011, 10:36 PM
Prove It
Re: simple equation
Quote:

Originally Posted by planetdomi
Im having difficulty understanding something simple:

Can someone show me how it is possible to get from

2a² = d²

to

d = a√2

many thanks

Well first of all, that answer is wrong, but anyway...

\displaystyle \begin{align*} d^2 &= 2a^2 \\ \sqrt{d^2} &= \sqrt{2a^2} \\ |d| &= \sqrt{2}\sqrt{a^2} \\ |d| &= \sqrt{2}\,|a|\textrm{ or, if you like} \\ d &= \pm \sqrt{2}\,a \end{align*}
• Sep 17th 2011, 10:46 PM
planetdomi
Re: simple equation
wow

Thankyou so much