What is the first term of the sequence? What is the common ratio between terms? Use these values in the explicit equation for geometric sequences.
F
Practice makes perfect
Explicit equations for geometric sequences follow a specific format.
a_n= a_1 r^(n-1)In this form, a_1 is the first term in a given sequence, r is the common ratio from one term to the next, and a_n is the {\color{#FF0000}{n}}^\text{th} term in the sequence. For this exercise, the first term is a_1= 5. Let's observe the other terms to determine the common ratio r.
5* 3 →15* 3 →45* 3 →135...
By substituting these two values into the explicit equation and simplifying, we can find the formula for this sequence.
