" 10.If the first,second and the last terms of an A.P.are "a,b,c" respectively,then the sum of the A.P.is "

If the first second and last terms of an A.P.are a,b and 2a respectively,then its sum is

The first, second and last terms of an A.P. are a, b, c respectively, then the sum to first n terms is

If the first second and the last terms of an A.P are a,band 2a , respectively, then its sum is

If the first,second and last term of an AP are a,b and 2a respectively,its sum is

First,Second and last terms of a finite A.P.are m,n and 2m respectively,then sum of the series is

The first , second and the last terms of an A.P. are a ,b , c respectively. Prove that the sum is ((a+c)(b+c-2a))/(2(b-a)) .

The first,second and the last terms of an A.P. are a,b,c respectively.Prove that the sum is (a+c)(b+c-2a)hline2(b-a)

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)) .