Core Connections Geometry, 2013
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Core Connections Geometry, 2013 View details
1. Section 5.1
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Exercise 19 Page 286

Practice makes perfect
a To determine if the sequence is arithmetic or geometric, we have to find out if there is a common difference or a common ratio between consecutive terms.
We have a common ratio between consecutive terms, which means this is a geometric sequence. The formula for a geometric sequence follows a certain format. a_n=a_0( b)^n In the formula, n is the term number, b is the common ratio and a_0 is the zeroth term. We have already determined that the common ratio is b= 110. Let's add this to the formula. a_n=a_0( 1/10)^n To find the zeroth term we can, for example, substitute a_1=100 in the formula and solve for a_0.
a_n=a_0(1/10)^n
a_1=a_0(1/10)^1
a_1=a_0(1/10)
100=a_0(1/10)
1000=a_0
a_0= 1000
Now we can complete the equation. a_n=1000(1/10)^n
b Like in Part A, we will first determine if this is a geometric or an arithmetic sequence.
We have a common difference between consecutive terms, which means this is an arithmetic sequence. The formula for an arithmetic sequence follows a certain format. a_n= mn+a_0 In the formula, n is the term number, m is the common difference, and a_0 is the zeroth term. We have determined that the common difference is m= - 50. a_n= - 50n+a_0 To find the zeroth term we can, for example, substitute a_1=0 in the formula and solve for a_0.
a_n=- 50n+a_0
a_1=- 50( 1)+a_0
a_1=- 50+a_0
0=- 50+a_0
50=a_0
a_0= 50
Now we can complete the equation. a_n=- 50n+50