So I have this seemingly simple, but I just don't see how this works?

\(\displaystyle

\frac{C[(M_1 + M_2) \pm \sqrt{(M_1 + M_2)^2 - (M_1 M_2)(Ka)^2}]}{(M_1 M_2)}

\)

To

\(\displaystyle

\frac{C(M_1 + M_2)}{(M_1 M_2)} \left( 1 \pm \left[ 1 - \frac{(M_1 M_2) (Ka)^2}{2(M_1 + M_2)^2} \right] \right)

\)

please if you can solve this, explain every step that leads to the result.

pretty nasty eh? Or maybe I'm just stupid

Thanks

Chris