Question

Explain how you should use the formula to calculate the number of pennies on Rows 1-4. Why use the formula?

The formula is much faster.
Substitute in a1=1, r = 2, and n = 32 into the formula.

Answer 1

Sample Response:

The formula is much faster.

Substitute in a1=1, r = 2, and n = 32 into the formula.

Answer 2

`S_(n)=15`

Explanation:

from the question given i can infer that it is a geometric sequence. this question is asking for the sum of the first four pennies in on the row

therefore using the formula for the sum of a geometric sequence which is

`S_(n) =(a(r^(n)-1) )/(r-1)`

so substituting the values of a, r and n into the the equation above

`S_(4)=(1(2^(4)-1) )/(2-1)  \\S_(4) =(1(16-1))/(1) \\\\\S_(4) =1(15)\\S_(4) =15`