3)If 9th term of an AP is zero, prove that 29th term is double the 19th term.

Asked by  | 24th Dec, 2009, 09:18: AM

Expert Answer:

an = a1 + (n-1)d

a9 = a1 + 8d = 0; a1 = -8d

a29 = a1 + 28d = -8s + 28d = 20d...(1)

a19 = a1 + 18d = 10d .....(2)

Hence a29 = 2a19

Regards,

Team,

TopperLearning.

 

Answered by  | 24th Dec, 2009, 01:45: PM

Queries asked on Sunday & after 7pm from Monday to Saturday will be answered after 12pm the next working day.