Core Connections Geometry, 2013
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Core Connections Geometry, 2013 View details
2. Section 5.2
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Exercise 57 Page 301

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 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 already determined that the common difference is m= 1500. a_n= 1500n+a_0 To find the zeroth term we can, for example, substitute a_1=500 in the formula and solve for a_0.
a_n=1500n+a_0
a_1=1500( 1)+a_0
a_1=1500+a_0
500=1500+a_0
- 1000=a_0
a_0= - 1000
Now we can complete the equation. a_n=1500n+(- 1000) ⇔ a_n=1500n-1000
b Like in Part A, we will first determine if this is a geometric or an arithmetic sequence.
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= 5. a_n=a_0( 5)^n To find the zeroth term we can, for example, substitute a_1=30 in the formula and solve for a_0.
a_n=a_0(5)^n
a_1=a_0(5)^1
a_1=a_0(5)
30=a_0(5)
6=a_0
a_0= 6
Now we can complete the equation. a_n=6(5)^n