Write ∑mr=0n+rCr in the simplified form.
∑mr=0n+rCr =nC0+n+1C1+n+2C2+n+3C3+...+n+mCm =n!0!n!+(n+1)!1!n!+(n+2)!2!n!+(n+3)!3!n!+...+(n+m)!n!m!=(m!)(n!)+(n+1)!m!+(n+2)!m!+...+(n+m)!m!n!m!=(n+m+1)!m!(n+1)!=n+m+1Cn+1
If n is an odd natural number , then n∑r=0(−1)rrCr equals :