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)(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 the last terms of an A.P. are a,b,c respectively, then the sum of the A.P. is

The first,second and middle terms of an AP are a,b,c respectively.Their sum is

If the first second and last term of an A.P.are a,b, and 2a respectively then its sum is (ab)/(2(b-a)) b.(ab)/(b-a) c.(3ab)/(3(b-a)) d.none of these

If the first, second and last term of an A.P. are a ,\ b and 2a respectively, its sum is (a b)/(2(b-a)) (b) (a b)/(b-a) (c) (3a b)/(2(b-a)) (d) none of these

If the first second and third term of AP are a,b and 2 a respectively.Then the sum of the AP is

Sum of the first p,q and r terms of an A.P are a,b and c,respectively.Prove that quad (a)/(p)(q-r)+(b)/(q)(r-p)+(c)/(r)(p-q)=0

If the first,second and nth terms of a A.P. are respectively a,b and c then prove that the sum of n terms of this series is