Solutions to Span of Functions Problems

  • Context: Undergrad 
  • Thread starter Thread starter gummz
  • Start date Start date
  • Tags Tags
    Functions Span
Click For Summary

Discussion Overview

The discussion revolves around the concept of the span of functions, specifically whether a function can be considered in the span of two other functions when the coefficients in the linear combination are not constants. The scope includes theoretical aspects of linear combinations and vector spaces.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions if a function h can be in the span of functions f and g if the coefficients a and b are not constants.
  • Another participant asserts that h cannot be in the span of f and g if a and b are not constants, indicating a disagreement on the conditions for span.
  • A third participant clarifies that for h to be in the span of f and g, it must be expressed as a linear combination with constant coefficients, drawing a parallel to vector spaces.
  • A later reply requests more information about the specific vector space in question and whether the functions g and h are part of a basis for that space.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of constant coefficients for a function to be in the span of others, indicating unresolved disagreement on this aspect.

Contextual Notes

There is a lack of specificity regarding the vector space being discussed, which may influence the definitions and conditions applied to the span of functions.

gummz
Messages
32
Reaction score
2
So let's say I have a function that I want to find out if is in the span of two other functions, for example, a*f + b*g = h, where f, g, and h are functions, and a and b are constants. Let's say I find a solution where a and b are not constants. Does that still mean that h is in the span of f and g, even though a and b are not constants?
 
Physics news on Phys.org
gummz said:
Does that still mean that h is in the span of f and g, even though a and b are not constants?
No
 
For a function h to be in the span of two other functions f and g, h must be a linear combination of f and g. IOW, h = af + bg, where a and b are constants. It's almost exactly the same definition for a vector to be in the span of two other vectors.
 
It would be nice if the OP could be more specific about the vector space s/he is working in; gummz, can
you tell us more about what space you are working in? are g,h part of a basis for the space?
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 13 ·
Replies
13
Views
2K
  • · Replies 1 ·
Replies
1
Views
990
  • · Replies 23 ·
Replies
23
Views
2K
  • · Replies 14 ·
Replies
14
Views
4K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 15 ·
Replies
15
Views
5K
  • · Replies 26 ·
Replies
26
Views
1K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K