Facebook & Ranking Elo Formula

Eduardo Saverin (now a Singaporean billionaire investor) gave the wrong Elo formula to his Facebook co-founder Mark Zuckerburg, both of them became 'accidental' billionaire. Watch the video clip in the movie "Social Network":

http://m.youtube.com/#/watch?v=BzZRr4KV59I

The Elo formula is based on the theory of Normal Distribution with Logarithm function, from base of exponential e to base of 10.
The correct Elo Formula should be :
$Latex \boxed
{
E_a =\frac{1}
{1+ \frac{1}{400}.\Huge 10^{(R_b - R_a)}
}
}$

$Latex \boxed
{
E_b =\frac{1}
{1+ \frac{1}{400}.\Huge 10^{(R_a - R_b)}
}
}$

Eduardo had missed the power ^ below: