Do Sequences and Series Always Converge with Positive Decreasing Terms?

  • Thread starter Thread starter SPhy
  • Start date Start date
  • Tags Tags
    Intuition
SPhy
Messages
24
Reaction score
0
Just wanted to know if I'm approaching this problem correctly.

1. The Problem

A. If the terms of a sequence of all positive terms go to zero, then the sequence must converge? True or false. Provide an example.

B.If the terms of a series of all positive terms go to zero, then the series converges? True or false. Provide an example.

2. Attempt

A. True, consider the sequence ace sub n, starting at n = 0 and going to infinity, where ace sub n is 1/(n^4+2)

The terms of this sequence decrease to zero and the sequence converges and the limit is 0.

B. False, consider the Harmonic series 1/n, the limit as n--->inf = 0, but the terms do not decrease to 0.
 
Physics news on Phys.org
SPhy said:
Just wanted to know if I'm approaching this problem correctly.

1. The Problem

A. If the terms of a sequence of all positive terms go to zero, then the sequence must converge? True or false. Provide an example.

B.If the terms of a series of all positive terms go to zero, then the series converges? True or false. Provide an example.

2. Attempt

A. True, consider the sequence ace sub n, starting at n = 0 and going to infinity, where ace sub n is 1/(n^4+2)

The terms of this sequence decrease to zero and the sequence converges and the limit is 0.

B. False, consider the Harmonic series 1/n, the limit as n--->inf = 0, but the terms do not decrease to 0.

Please restate B more completely and carefully and be sure you answer the question. It is asking about a series.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...

Similar threads

Back
Top