Question

76. If the sum of first m terms of an AP is same
as the sum of its first n terms (m not =n), show
that the sum of its first (m + n) terms iszero ​

Answer 1

Hope you understand.

Regards,

Bhanu Pratap Pandit

Answer 2

Sm=Sn

m/2{2a+(m-1)d}=n/2{2a+(n-1)d

m/2{2a+dm-d}=n/2{2a+dn-d}

am-an+d/2(m+n)(m-n)-d/2(m-n)