Sequences and Series of Functions

In summary, the problem asks to prove that the integral from 0 to pi/2 of a function defined by a convergent series is equal to a specific sum involving the terms of the series. The student is stuck and seeking help, while another person suggests evaluating the integral explicitly and provides a solution using TeX notation.
  • #1
Fiz2007
6
0

Homework Statement



Let sum of a sub k
be an absolutely convergent series.

a. Let f be the function defined by f(x) = sum of (a sub k) * sin(kx). Prove that:

the integral from 0 to pi/2 of f = sum of (a2k-1 + a4k-2)/(2k-1)

Homework Equations



I already showed that f(x) converges uniformly using the Weirstrass M theorem

The Attempt at a Solution



I'm completely stuck. I understand convergence of sequences and proving uniform continuity of sequences, but when we begin to use the summation with the sequence of functions, I am totally lost. Any help would be greatly appreciated.
 
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  • #2
have you tried evaulating the integral explicitly?
 
  • #3
also to write in tex see below
[tex] \int^{\pi/2}_0 dx f = \int^{\pi/2}_0 dx \sum a_k sin(kx)[/tex]
 

Related to Sequences and Series of Functions

1. What is a sequence of functions?

A sequence of functions is a set of functions that are indexed by natural numbers. Each function in the sequence has a specific input and output, and the sequence can be thought of as a list of functions.

2. What is a series of functions?

A series of functions is the sum of a sequence of functions. It is similar to a regular arithmetic series, but instead of adding numbers, we are adding functions.

3. What is the difference between a pointwise and uniform convergence of a sequence of functions?

Pointwise convergence means that for each input, the sequence of function values approaches the same limit. Uniform convergence means that the sequence of functions as a whole approaches the same limit, regardless of the input.

4. How do you determine if a sequence of functions is convergent or divergent?

To determine convergence or divergence of a sequence of functions, you can use the limit comparison test, ratio test, or root test. These tests compare the given sequence to a known convergent or divergent sequence to determine its behavior.

5. What are some real-world applications of sequences and series of functions?

Sequences and series of functions are used in many fields of science, including physics, engineering, and biology. For example, they are used to model physical phenomena, such as the motion of a pendulum or the growth of a population. They are also used in numerical analysis to approximate complicated functions and in signal processing to analyze and manipulate data.

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