Posted by sarah on Sunday, June 5, 2011 at 5:17pm.
Is this an arithmetic progression (AP) or geometric progression (GP)?
AP's have constant differences, while GP's have constant ratios.
Given series:
7, 11, 15, 19, 23
differences:
11-7=4, 15-11=4, 19-15=4, 23-19=4
(constant difference d=4, therefore AP)
ratios:
11/7, 15/11, 19/15, 23/19 (different, so NOT GP).
The nth term of an AP is:
A(n)=A(1)+(n-1)d
d=4
A(n)=A(1)+(n-1)d
=7+(n-1)4
=7+4n-4
=3+4n
it just says work out the nth term for the those numbers
I hope you did not just read the first line of my response.
I was asking myself that question (hope you do the same). The rest of the response followed.