218k views
4 votes
Find the sum of the geometric sequence: 1,2,4,8,16,…
a. 93
b. 24
c. 31
d. 63

1 Answer

4 votes

Final answer:

The sum of the provided geometric sequence 1, 2, 4, 8, 16 is 31, obtained by adding all the terms together.

Step-by-step explanation:

The sum of the geometric sequence 1, 2, 4, 8, 16 is 31.Geometric sequences expand by a consistent factor with each term. In this sequence, each term is double the previous one. To find the sum of a geometric sequence, sum the terms: 1 + 2 + 4 + 8 + 16 = 31. This particular sequence is a finite geometric series, where the ratio (common multiplier) is 2. Start with the first term and continue multiplying by 2 until the last term is reached, summing all the terms.The sum of a geometric sequence can be found using the formula:

Sum = a * (1 - r^n) / (1 - r)where 'a' is the first term, 'r' is the common ratio, and 'n' is the number of terms.In this case, the first term is 1 and the common ratio is 2. The sum can be calculated as:Sum = 1 * (1 - 2^n) / (1 2)Simplifying the expression gives:Sum = (2^n - 1) / (1 - 2)Since we are asked to find the sum of the sequence up to 'a', we need to find the value of 'n' that corresponds to the given 'a'.Solving the equation 2^n = a, we find that n = log(base 2) of a.Plugging in the value of 'a' into the formula:Sum = (2^(log(base 2) of a) - 1) / (1 - 2)Sum = a - 1Therefore, the sum of the geometric sequence is a - 1.

User BrunoVT
by
7.7k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories