1. anonymous

2. anonymous

how do i get from the middle term to the last term....not seeing what happened

3. anonymous

Okay i'll just give the answer:$\frac{(2n+2)!n!}{2n!(n+1)!}=\frac{(2n+2)(2n+1)!n!}{2n!(n+1)n!}=\frac{(2n+2)(2n+1)(2n)!n!}{2n!(n+1)n!}$