Question
The table below gives the positions of three terms in an arithmetic sequence What is the n^ (th ) term rule for the sequence? Position, n & ldots & 100 & 101 & 102 Term & ldots & 324 & 327 & 330
Answer
4.4
(301 Votes)
Lexi
Master · Tutor for 5 years
Answer
The
term rule of the sequence is \(a_n = 27 + 3(n-1)\)
Explanation
## Step 1: Identify the common difference of the arithmetic sequenceBy looking at the given numbers in the sequence, namely
,
, and
, we can see that the common difference,
, is
.## Step 2: Identify the first term of the sequenceSince the common difference is known, the first term of the sequence can be found by subtracting [(position - 1)
common difference] from any known term. Let's take the
term, subtracting
(This consists of 99 steps of +3 from the first term)### \(a _ { 1 } = a - (n-1) \cdot d\)### \(a_{1} = 324 - (100-1) \cdot 3\)###
## Step 3: Write out the nth term rule for the sequenceThe "nth term" or general rule of an arithmetic sequence is \(a_n = a_1 + (n-1)d\), where
is the nth term,
is the first term,
is the common difference and
is the term number. Substituting the values that we computed before for
and
, the formula becomes### \(a_n = 27 + 3(n-1)\)This formula allows you to find any term in the sequence knowing its position.