Big Ideas Math Algebra 2, 2014
BI
Big Ideas Math Algebra 2, 2014 View details
3. Analyzing Geometric Sequences and Series
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Exercise 60 Page 431

a Let be the number of divers in the ring. To determine a rule for the given geometric sequence, we will use the formula for the explicit rule of geometric sequences.
In our case, since there are divers in the first ring the first term is Because each ring after the first has twice as many skydivers as the preceding ring, its common ratio is Next, we will substitute values for and into the explicit rule of geometric sequences.
b We are asked to find the total number of skydivers when there are four rings. From Part A we know that the number of skydivers in the ring is a geometric sequence ,with and Next, we will use the formula for finding partial sums of geometric series.
We want to calculate the sum of the first terms. So, Let's substitute the values and find the sum.
Simplify right-hand side
Therefore, there are skydivers in all four rings.