G Glen88 Member Joined Nov 6, 2005 Messages 39 Location Equatorial Guinea Gender Male HSC 2006 Jun 18, 2006 #1 Need some help with this. If 2nPn = 8. 2n-1Pn-1 , Find the Value of n.
S SoulSearcher Active Member Joined Oct 13, 2005 Messages 6,757 Location Entangled in the fabric of space-time ... Gender Male HSC 2007 Jun 18, 2006 #2 Glen88 said: Need some help with this. If 2nPn = 8. 2n-1Pn-1 , Find the Value of n. Click to expand... 2nPn = 8. 2n-1Pn-1 i.e. (2n)!/(2n-n)! = 8 * (2n-1)!/[2n-1-(n-1)]! (2n!)/n! = 8 * (2n-1)!/n! [(2n)! - 8(2n-1)!]/n! = 0 (2n)! - 8(2n-1)! = 0 2n(2n-1)! - 8(2n-1)! = 0 (2n-8)(2n-1)! = 0 2n - 8 = 0, as (2n-1)! cannot equal zero 2n = 8 n = 4
Glen88 said: Need some help with this. If 2nPn = 8. 2n-1Pn-1 , Find the Value of n. Click to expand... 2nPn = 8. 2n-1Pn-1 i.e. (2n)!/(2n-n)! = 8 * (2n-1)!/[2n-1-(n-1)]! (2n!)/n! = 8 * (2n-1)!/n! [(2n)! - 8(2n-1)!]/n! = 0 (2n)! - 8(2n-1)! = 0 2n(2n-1)! - 8(2n-1)! = 0 (2n-8)(2n-1)! = 0 2n - 8 = 0, as (2n-1)! cannot equal zero 2n = 8 n = 4
G Glen88 Member Joined Nov 6, 2005 Messages 39 Location Equatorial Guinea Gender Male HSC 2006 Jun 18, 2006 #3 SoulSearcher said: 2nPn = 8. 2n-1Pn-1 i.e. (2n)!/(2n-n)! = 8 * (2n-1)!/[2n-1-(n-1)]! (2n!)/n! = 8 * (2n-1)!/n! [(2n)! - 8(2n-1)!]/n! = 0 (2n)! - 8(2n-1)! = 0 2n(2n-1)! - 8(2n-1)! = 0 (2n-8)(2n-1)! = 0 2n - 8 = 0, as (2n-1)! cannot equal zero 2n = 8 n = 4 Click to expand... Thanks.
SoulSearcher said: 2nPn = 8. 2n-1Pn-1 i.e. (2n)!/(2n-n)! = 8 * (2n-1)!/[2n-1-(n-1)]! (2n!)/n! = 8 * (2n-1)!/n! [(2n)! - 8(2n-1)!]/n! = 0 (2n)! - 8(2n-1)! = 0 2n(2n-1)! - 8(2n-1)! = 0 (2n-8)(2n-1)! = 0 2n - 8 = 0, as (2n-1)! cannot equal zero 2n = 8 n = 4 Click to expand... Thanks.
