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In Mathematics / High School | 2025-07-03

$0.25+1+4+16+64$

Enter the values used in finding a partial sum.
$r=4 \quad a_1=0.25 \quad n=\square$

Asked by Loverchildbee

Answer (1)

To find the partial sum of the series given by the sequence 0.25 + 1 + 4 + 16 + 64 , we can analyze it as a geometric sequence.
A geometric sequence is one where each term after the first is found by multiplying the previous one by a fixed, non-zero number called the common ratio r .

Identify the terms of the sequence :


The sequence provided is 0.25 , 1 , 4 , 16 , 64 .


Determine the first term a 1 ​ :


The first term a 1 ​ is given as 0.25 .


Find the common ratio r :


To find the common ratio, divide the second term by the first term: r = 0.25 1 ​ = 4

We can check this by confirming that each subsequent term maintains this ratio: 1 4 ​ = 4 , 4 16 ​ = 4 , 16 64 ​ = 4



Count the number of terms n :


The series has the terms 0.25 , 1 , 4 , 16 , 64 . Thus, there are 5 terms.

In conclusion, the values used in finding the partial sum are r = 4 , a 1 ​ = 0.25 , and n = 5 .

Answered by DanielJosephParker | 2025-07-07