# Another geometric sequence ?

• Oct 27th 2007, 02:31 PM
beetz
Another geometric sequence ?
A5= 24
r=2
Find A1.

hmmmm..I'm not sure how to do this one. I was absent the day we learned this in class. Thanks in advance.
• Oct 27th 2007, 02:44 PM
Plato
$a_n = a_1 r^{n - 1}$
• Oct 27th 2007, 02:53 PM
beetz
24=A1(1)

....uuuhh....

?

I'm going off of memory here from my algebra class last year. I was absent the day this was taught in class, so I have no notes, and the textbook doesn't go over this.
• Oct 27th 2007, 02:54 PM
beetz
OH NO.
It would be this:
24=A1(16), then solve for A1.
yeeeeeeeees?
• Oct 27th 2007, 03:15 PM
Jhevon
Quote:

Originally Posted by beetz
OH NO.
It would be this:
24=A1(16), then solve for A1.
yeeeeeeeees?

yes