BINOMIAL IDENTITIES


This quiz is about two identities involving the binomial coefficients, 

   2 Sum0..M k ( 2M choose k ) = M 22M





   4 Sum0..M (M - k)2 ( 2M choose k ) = M 22M
Hint.
Use the identity 
   k ( r choose k ) = r ( r-1 choose k-1 )

Marco Corvi - 2016