Let an be the nth term of an A.P if ∑r=1100 a2r=α and ∑r=1100 a2r−1=β then the common difference of the A.P is:
α−β200
α−β
α−β100
β-α
α=a2+a4+a6+……………+a200β=a1+a3+a5+………..+a199α−β=a2−a1+a4−a3+a6−a5+……..+a200−a199α−β=d+d+d+………….+d=100dd=(α−β)100