the first term of a geometric sequence is 5 and the common ratio is 6.

1) create an equation for the situation
2) find the 5th term of the sequence

1 answer

  1. In a geometric sequence, the \( n \)-th term can be expressed using the formula:

\[ a_n = a_1 \cdot r^{(n-1)} \]

where:

  • \( a_n \) is the \( n \)-th term,
  • \( a_1 \) is the first term,
  • \( r \) is the common ratio,
  • \( n \) is the term number.

For this specific geometric sequence:

  • The first term \( a_1 = 5 \)
  • The common ratio \( r = 6 \)

Thus, the equation for this geometric sequence is:

\[ a_n = 5 \cdot 6^{(n-1)} \]

  1. To find the 5th term of the sequence (\( n = 5 \)), we can substitute \( n \) into the equation:

\[ a_5 = 5 \cdot 6^{(5-1)} = 5 \cdot 6^{4} \]

Now, we calculate \( 6^4 \):

\[ 6^4 = 6 \cdot 6 \cdot 6 \cdot 6 = 1296 \]

Then substitute back into the equation:

\[ a_5 = 5 \cdot 1296 = 6480 \]

Therefore, the 5th term of the sequence is 6480.