Home > Precalculus > Sums of Geometric Sequences

What is the sum of the geometric sequence 8, 16, 32?

Answer 1

The sum of the geometric sequence is 56.

To find the sum of any geometric sequence, you use the equation: #S_n = (a(r^n -1))/(r-1)#where:

a --> is the first term of the sequence; in this case "a" is 8.

r --> is the ratio (what each number is being multiplied by) between each number in the sequence; in this case, each term is being multiplied by 2.

n --> is the number of terms in the sequence; in this case, there are 3 terms.

Knowing the value of each variable, you can substitute the values into the equation as follows:

#S_n = (8(2^3 -1))/(2-1)#

Simplify and solve:

#S_n = (56)/(1)#

Therefore, the sum of the sequence is 56! Hopefully you've understood this and hopefully I was of some help! :)

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.