I have asked this question all over reddit but can't seem to find an answer. I hope it's not the same here.
How do you get from equation one to equation two? I have tried so many methods but couldn't get the same answer.
I tried $E^{2} = m^{2}c^{4} + p^{2}c^{2}$ but got a different term in the radical of $$ cp' = h\left(\omega + \omega'\right) \pm \sqrt{h\omega' - m^{2}c^{4}} $$
Could someone show me the steps for how you get the initial and final momentum $?$.
