Polynomial convergence question.

In summary, when using the comparison test to find convergence, it is not recommended to divide by the largest n in the denominator. This is because dividing by the largest n only applies to limits, not infinite sums. The comparison test suggests using the limit of a sequence instead.
  • #1
rcmango
234
0

Homework Statement



To find convergence, why can't I divided by the largest n in the denominator in this problem: SUM n_infinity 1/(n^2 - 4n + 4) ?

its suggested to use the comparison test.

(I think SUM stands for E Reimann sum correct?)

but in this problem, I can easily find convergence by dividing by large n in the denominator: lim n->infinity 3n^2/(7n^2 + 1)

?

any explanation please. thanks.

Homework Equations





The Attempt at a Solution



its all above. thanks.
 
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  • #2
Basically, because one is a limit and one is a sum.
 
  • #3
Okay, so for a limit, its okay to divide by the largest N, but for a sum it is not common?
 
  • #4
Do you understand why dividing by the largest power of N, in both numerator and denominator helps you find the limit of a sequence? Would that apply to an infinite sum?
 

What is polynomial convergence?

Polynomial convergence refers to the behavior of a mathematical sequence or series that approaches a limit value as the degree of the polynomial increases. In other words, as the degree of the polynomial increases, the values of the sequence or series get closer and closer to a specific value.

How do you determine if a polynomial converges?

A polynomial converges if its degree is even and the leading coefficient is positive. To determine if a polynomial converges, you can also use the ratio test or the root test, which are mathematical tests that determine the convergence or divergence of a series.

What is the importance of polynomial convergence?

Polynomial convergence is important because it allows us to approximate complex functions using simpler polynomial functions. This can greatly simplify calculations and make them more manageable. Additionally, polynomial convergence is used in many fields such as physics, engineering, and economics to model and solve real-world problems.

Can a polynomial converge to more than one value?

No, a polynomial can only converge to one value. This is because a polynomial is a function with a single output for every input. Therefore, as the degree of the polynomial increases, the values of the function will get closer and closer to a single value, which is its limit.

What is the difference between polynomial convergence and uniform convergence?

The main difference between polynomial convergence and uniform convergence is the rate at which the sequence or series approaches its limit value. In polynomial convergence, the values get closer to the limit at a decreasing rate, while in uniform convergence, the values get closer at a constant rate. Additionally, in uniform convergence, the rate of convergence is the same at every point in the domain, whereas in polynomial convergence, the rate may vary at different points.

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