Welcome to Westonci.ca, the place where your questions are answered by a community of knowledgeable contributors. Explore a wealth of knowledge from professionals across different disciplines on our comprehensive platform. Experience the convenience of finding accurate answers to your questions from knowledgeable experts on our platform.

What is the 8th term in the geometric sequence described by this explicit formula?

[tex]\[ a_n = 6 \cdot 3^{(n-1)} \][/tex]


Sagot :

To find the 8th term in the given geometric sequence, we start by identifying the necessary components of the sequence formula:

The explicit formula for a geometric sequence is given by:
[tex]\[ a_n = a_1 \cdot r^{(n-1)} \][/tex]
where:
- \( a_n \) is the n-th term we want to find,
- \( a_1 \) is the first term of the sequence,
- \( r \) is the common ratio,
- \( n \) is the term number.

From the given formula \( a_n = 6 \cdot 3^{(n-1)} \), we can see:
- The first term, \( a_1 \), is 6.
- The common ratio, \( r \), is 3.
- We need to find the 8th term, so \( n = 8 \).

Next, we substitute the given values into the formula:
[tex]\[ a_8 = 6 \cdot 3^{(8-1)} \][/tex]
Simplify the exponent:
[tex]\[ 8-1 = 7 \][/tex]
So the expression becomes:
[tex]\[ a_8 = 6 \cdot 3^7 \][/tex]

Now, calculate \( 3^7 \):
[tex]\[ 3^7 = 2187 \][/tex]

Finally, multiply this result by the first term:
[tex]\[ a_8 = 6 \cdot 2187 = 13122 \][/tex]

Thus, the 8th term in the geometric sequence is:
[tex]\[ a_8 = 13122 \][/tex]