# A.P.

• September 12th 2009, 11:39 PM
aman
A.P.
If (m+1)th term of A.P. is twice the (n+1)th term . Then show that (3m+1)th term is twice the (m+n+1)th term.

I'm confused with this one. No idea how to do this. Any help wpuld be appriciated.
• September 13th 2009, 12:09 AM
CaptainBlack
Quote:

Originally Posted by aman
If (m+1)th term of A.P. is twice the (n+1)th term . Then show that (3m+1)th term is twice the (m+n+1)th term.

I'm confused with this one. No idea how to do this. Any help wpuld be appriciated.

You are given:

$a+(m+1)\rho=2(a+(n+1)\rho)$

Then

$a+(3m+1)\rho=a+(m+1)\rho+2m\rho= ...$

CB
• September 13th 2009, 12:23 AM
psparmar