Proving Integral Norms on C[0,1] for Continuous Functions

In summary, the conversation discusses how to prove that the functions ||f||1 = ∫|f| and ||f||= ∫t|f(t)|dt define norms on the subspace C[0,1] of continuous functions. The conversation also mentions the conditions for proving that ||v||>0 and ||v||=0 implies v=0, and uses the property of integrals to show the validity of these norms.
  • #1
cummings12332
41
0

Homework Statement


show that ||f||1 = ∫|f| (integral from 0 to 1) does define a norm on the subspace C[0,1] of continuous functions

and also the same for ||f||= ∫t|f(t)|dt is a norm on C[0,1]


Homework Equations



(there are 3 conditions , i just don't know how to prove that ||v||>0,||v||=0 implies v=0)
 
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  • #2
cummings12332 said:

Homework Statement


show that ||f||1 = ∫|f| (integral from 0 to 1) does define a norm on the subspace C[0,1] of continuous functions

and also the same for ||f||= ∫t|f(t)|dt is a norm on C[0,1]

Homework Equations



(there are 3 conditions , i just don't know how to prove that ||v||>0,||v||=0 implies v=0)

If a continuous function is nonzero (or positive) at a point, what about its value nearby that point, and why?
 
  • #3
LCKurtz said:
If a continuous function is nonzero (or positive) at a point, what about its value nearby that point, and why?

yes if it is not zero ,then |f(x)-f(c)|<esillope then choose esillope to be f(c)/2 then it will get |f(x)|>sth... but how can u ensure that f(c) >0 for esillope has to be >0
 
  • #4
cummings12332 said:
yes if it is not zero ,then |f(x)-f(c)|<esillope then choose esillope to be f(c)/2 then it will get |f(x)|>sth... but how can u ensure that f(c) >0 for esillope has to be >0

You have this property of integrals to work with: If ##f,g\in C[a,b]## and ##f(x)> g(x)## on [a,b] then ##\int_a^b f(x)\, dx > \int_a^b g(x)\, dx##
 
  • #5
LCKurtz said:
You have this property of integrals to work with: If ##f,g\in C[a,b]## and ##f(x)> g(x)## on [a,b] then ##\int_a^b f(x)\, dx > \int_a^b g(x)\, dx##

yes,i worked out the first one now,but how about the secound one for t f(t) i don't know how to construct the inequality that u have mentioned above..
 

1. What is integral norm proving?

Integral norm proving is a method used in mathematics and computer science to prove the equivalence of two mathematical expressions or functions by showing that their integrals over a certain interval are equal.

2. When is integral norm proving used?

Integral norm proving is commonly used in fields such as functional analysis, real analysis, and computational mathematics to prove the equivalence of functions or expressions, especially when other methods of proof may be difficult or impossible.

3. How does integral norm proving work?

Integral norm proving involves breaking down the two expressions or functions into smaller, simpler components and then showing that the integral of each component is equal. This is typically done using mathematical techniques such as substitution, integration by parts, and trigonometric identities.

4. What are the benefits of using integral norm proving?

Using integral norm proving can provide a more rigorous and general proof of equivalence compared to other methods. It also allows for the use of various mathematical techniques and can be applied in a wide range of fields.

5. Are there any limitations or challenges to using integral norm proving?

One limitation of integral norm proving is that it may not always be possible to break down an expression or function into smaller components. In addition, it can be time-consuming and require a strong understanding of mathematical concepts and techniques.

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