Can someone please look at the attached pdf and tell me how the top part is siomplified to the bottom.

 

The two terms under the square root sign have a common factor of 4ω^2. The square root of that common factor is 2ω which moves out from under the square root sign. Factoring is basic algebra -- were you asleep when that was covered?

 

Im pretty rubbish at maths and forget about simplifying most of the time. Im not mathematical so I tend to remember maths mechanically from memory.

 

Me too. I have great difficulty with abstract thought