If the first, second and last terms of A.P. be a, b, and c respectively, show that the sum of all
Channel: Doubtnut
Date: 2020-05-09

If the first, second and last terms of A.P. be a, b, and c respectively, show that the sum of all terms of the A.P. is `((a+c)(b+c-2a))/(2(b-a))`.