# Sequences

• Oct 24th 2008, 03:31 AM
magentarita
Sequences
Determine whether the given sequence is arithmetic, geometric or neither. If the sequence is arithmetic, find the common difference; if the sequence is geometric, find the common ratio.

(1) {8 - 3n/4}

(2) {(5/4)^n}
• Oct 25th 2008, 01:04 AM
CaptainBlack
Quote:

Originally Posted by magentarita
Determine whether the given sequence is arithmetic, geometric or neither. If the sequence is arithmetic, find the common difference; if the sequence is geometric, find the common ratio.

(1) {8 - 3n/4}

(2) {(5/4)^n}

For an arithmetic sequence there are constants \$\displaystyle a\$ and \$\displaystyle b\$ such that the \$\displaystyle n\$-th term can be written in the form:

\$\displaystyle a+bn\$

For a geometric sequence there are constants \$\displaystyle a\$ and \$\displaystyle b\$ such thatthe \$\displaystyle n\$-th term can be written in the form:

\$\displaystyle ab^n\$.

Now look at the two cases given in your question and you shound be able to answer this your self.

CB
• Oct 25th 2008, 04:53 AM
magentarita
Thanks...
Quote:

Originally Posted by CaptainBlack
For an arithmetic sequence there are constants \$\displaystyle a\$ and \$\displaystyle b\$ such that the \$\displaystyle n\$-th term can be written in the form:

\$\displaystyle a+bn\$

For a geometric sequence there are constants \$\displaystyle a\$ and \$\displaystyle b\$ such thatthe \$\displaystyle n\$-th term can be written in the form:

\$\displaystyle ab^n\$.

Now look at the two cases given in your question and you shound be able to answer this your self.

CB

Thank you so much. I will take it from here.