Question

If S be the sum of (2n+1) terms of an A.P( Arithematics Progression) and S1 that of alternate terms beginning with the first , then how to prove : S/S1 = (2n+1)/ (n+1)

Answer 1

S= (2n+1)(a + (2n+1 -1)d)/2
S1 is another AP with common difference =2d
if S has 2n+1 terms,,S1 will have n+1 terms
so S1= (n+1)(a + (n+1 -1)2d)/2
now calculate S/S1 and you get your ans

Answer 2

Thanks a lot

Answer 3

^_^