If (1+x)n = 1+C1x+C2x2+C3x3+……………………+Cnxn

1 ) Prove that: C0/1 - C1 /2 + C2/3 - ……………………………+ (-1)n Cn /(n+1) = 1/(n+1)

2) Prove that : C0/1 + C1 /2 + C2/3 + ……………………………+ Cn /(n+1) = {2(n+1) - 1}/(n+1)

3 ) Prove that : C1/ C0 + 2C2 / C1+ 3C3/ C2 +……………………………+ n .Cn / Cn -1 = n(n+1)/2