Learn to determine the 18th term of a geometric sequence by using the explicit formula

The video tutorial explains how to identify a geometric sequence by determining the common ratio. It demonstrates calculating the common ratio using the first two terms and verifying it with other terms. The tutorial then shows how to use the explicit formula to find the 18th term in the sequence, requiring a calculator for large calculations. The process involves applying the formula a_n = a_1 * r^(n-1) and calculating the result.

What is the first step in determining if a sequence is geometric?

• Multiply the first term by a constant.

• Find the common ratio by dividing the first two terms.

• Identify the first term of the sequence.

• Check if the sequence has a common difference.

How can you verify the common ratio in a geometric sequence?

• By adding the ratio to each term.

• By dividing each term by the previous term.

• By subtracting the ratio from each term.

• By multiplying each term by the ratio.

What does the explicit formula for a geometric sequence help you find?

• The average of the sequence.

• Any specific term in the sequence.

• The sum of all terms in the sequence.

• The common difference of the sequence.

In the formula a_n = a_1 * r^(n-1), what does 'n' represent?

• The sum of the sequence.

• The position of the term in the sequence.

• The common ratio of the sequence.

• The first term of the sequence.

Why is a calculator necessary when finding the 18th term in this example?

• Because the common ratio is a fraction.

• Because the numbers are too small.

• Because the numbers are too large.

• Because the sequence is not geometric.