There are 10 terms in the geometric progression.

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Homework Help Overview

The problem involves determining the number of terms in a geometric progression defined by the sequence 3, 6, 12, ..., 1536. Participants are exploring the relationship between the terms and the common ratio.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the formula for the nth term of a geometric progression and question the validity of the calculations presented. There are suggestions to simplify the equation by dividing both sides by 3 and to check if 1536 divided by 3 is a power of 2.

Discussion Status

The discussion is ongoing, with some participants providing guidance on how to approach the problem by calculating powers of 2. There are also critiques of the calculations presented, indicating a lack of consensus on the correctness of the initial attempts.

Contextual Notes

Some participants note potential errors in the original poster's work and emphasize the need for proper notation in exponent expressions. There is an indication that assumptions about the geometric nature of the sequence are being questioned.

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Homework Statement



3,6,12...1536
determine the number of terms in the progression

Homework Equations





The Attempt at a Solution


a=3 r=2

n= ar^n-1

1536= (3) (2)^n-1
 
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Okay, so solve it! First, divide both sides by 3. If that sequence is actually geometric, you should be able to identify 1536/3 as a power of 2. I suggest you just calculate powers of 2: 1, 2, 4, 8, 16, ... until you get to that number.
 
HallsofIvy said:
Okay, so solve it! First, divide both sides by 3. If that sequence is actually geometric, you should be able to identify 1536/3 as a power of 2. I suggest you just calculate powers of 2: 1, 2, 4, 8, 16, ... until you get to that number.

1536= (3) (2)^n-1

1536/3 = 6^n-1[itex]/[/itex]3

512 = 2^n-1

512 = 2^10-1

512 = 2^9

n = 10
 
nae99 said:
1536= (3) (2)^n-1

1536/3 = 6^n-1[itex]/[/itex]3

512 = 2^n-1

512 = 2^10-1

512 = 2^9

n = 10
There are errors in your work. Also, you need parentheses around your exponent expressions.
nae99 said:
1536= (3) (2)^(n-1)

1536/3 = 6^n-1[itex]/[/itex]3
The above is incorrect. 3*2^(n - 1) [itex]\neq[/itex] 6^(n - 1)
nae99 said:
512 = 2^n-1
The above is also incorrect. [6^(n - 1)]/3 [itex]\neq[/itex] 2^(n - 1)
nae99 said:
512 = 2^10-1

512 = 2^9

n = 10
 
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