I am haunted by an equation which I could simplify it with hand and it equals to $-i$ (complexe number). But, I don't know how to use maplesoft to simplify it. The equation takes the form of:
-Omega*a*sqrt(2)*sqrt(-Omega^2*a^2-2*k*m+sqrt(Omega^2*a^2*(Omega^2*a^2+4*k*m)))/(-Omega^2*a^2+sqrt(Omega^2*a^2*(Omega^2*a^2+4*k*m)))
$-{\frac {\Omega\,a\sqrt {2}\sqrt {-{\Omega}^{2}{a}^{2}-2\,km+\sqrt {{ \Omega}^{2}{a}^{2} \left( {\Omega}^{2}{a}^{2}+4\,km \right) }}}{-{ \Omega}^{2}{a}^{2}+\sqrt {{\Omega}^{2}{a}^{2} \left( {\Omega}^{2}{a}^{ 2}+4\,km \right) }}} $
Thank you in advance for taking a look. I'am sorry for not clarifying that the $a$ , $k$, $\Omega$ and $m$ are positive variables.