What are you trying to solve for?
Or are you trying to get from the first equation to the second?
There are two typos in your problem.
I don't see where that "2" comes from.
Also, you left out the square-root in the second expression.
How we get from: .
. . . to: .
Under the radical, we have: .
Multiply the second term by
. . .
Take the square root: . .
Substitute into the original expression:
I think I got it, the square root disappears because I can do a Binomial Approximation which states:
Therefore solving the two missing "2"s you were saying. Am i correct?
P.S. This was part of a physics problem I have (Solid State Physics), which the algebra was kind of horrible to solve as you can see from the above...