Is \(\frac{1/0}{1/0}\) Equal to 1 or Undefined?

  • Context: High School 
  • Thread starter Thread starter eNathan
  • Start date Start date
Click For Summary

Discussion Overview

The discussion revolves around the expression \(\frac{1/0}{1/0}\) and whether it can be considered equal to 1 or if it is undefined. Participants explore the implications of division by zero, the nature of undefined values in mathematics, and related concepts such as infinity and limits.

Discussion Character

  • Debate/contested
  • Mathematical reasoning
  • Conceptual clarification

Main Points Raised

  • Some participants argue that \(\frac{1/0}{1/0}\) is undefined because division by zero is not defined in mathematics.
  • Others suggest that if both terms are undefined, it might be possible to consider their quotient as 1, drawing parallels to the expression \(x/x\) where \(x\) is not zero.
  • A participant questions the validity of treating undefined quantities similarly to variables, suggesting that undefined does not equate to a number.
  • Some participants discuss the implications of infinity in arithmetic operations, noting that operations involving infinity are also not well-defined.
  • There is mention of L'Hôpital's Rule in the context of limits, emphasizing that it applies to indeterminate forms rather than direct algebraic manipulation of undefined expressions.
  • One participant presents a limit example to argue that \(\frac{1/0}{1/0}\) could approach 0, though this is challenged as not being a proof.
  • Another participant highlights that the concept of undefined is nuanced and varies based on context, particularly in relation to piecewise functions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether \(\frac{1/0}{1/0}\) is equal to 1 or undefined. Multiple competing views remain, with some firmly stating it is undefined while others explore the possibility of it being equal to 1 under certain interpretations.

Contextual Notes

The discussion includes various assumptions about the nature of undefined values and the treatment of infinity in mathematics. There are unresolved mathematical steps and differing definitions of what constitutes an undefined expression.

  • #31
No, you cannot. "a;kljdfa;lkjasdf" is undefined, and thus so is any expression involving it.

You also cannot say "a;kljdfa;lkjasdf = a;kljdfa;lkjasdf"
 
Mathematics news on Phys.org
  • #32
Then, how can an undefined entity differ from itself? If they are the same, comparing sames doesn't equal one?
 
  • #33
but the implication of [x / 0] / [x / 0] = 1 is perposterous. but you are right in saying that it can be manipulated to get a numerical result
 
  • #34
also, can't you apply geomtric reasoning, since we DO know what happens to C/X when X approaches 0?
 
  • #35
Then, how can an undefined entity differ from itself?

It is just as invalid to say "a;kljdfa;lkjasdf \neq a;kljdfa;lkjasdf" as it is to say "a;kljdfa;lkjasdf = a;kljdfa;lkjasdf".
 
  • #36
The point is, you can't write any valid equation involving something that doesn't exist!
 
  • #37
mathmike said:
but the implication of [x / 0] / [x / 0] = 1 is perposterous. but you are right in saying that it can be manipulated to get a numerical result

To say that it equals zero is even more preposterous. I think we've reached a conclusion for this thread: abstract concepts cannot follow all of the same rules as concrete numbers.
 
  • #38
No matter how "abstract" a object is (in mathematics), it is still defined "as rigorously" as something more "concrete". Different objects obey different rules, but some objects don't have laxer rules making them less well-defined.
 
  • #39
Agreed. My only point was that you cannot apply all of the rules of algebra to infinity and division by zero.
 
  • #40
yes but i can show that the limit is zero when x approches 0 but it cannot be shown in any manner that it is 1. so saying it is zero is not perposterous, in fact it follows l'hospital's therom. can you show that the limit is in any way 1.
 
  • #41
The limit of the particular function you mentioned is zero. Limits of the form inf/inf generally are not zero.
 
  • #42
actually more often than not they are zero.
 
  • #43
What do you mean by "more often than not"? You took the example of f(x)=x/e^x, but one could just as easily take f(x)=(e^x)/x, which clearly approaches infinity as x approaches infinity. And in any case, niether example shows what (1/0)/(1/0) is equal to, they simply show how some particular functions behave as they approach this.
 

Similar threads

  • · Replies 66 ·
3
Replies
66
Views
7K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 36 ·
2
Replies
36
Views
5K
  • · Replies 17 ·
Replies
17
Views
6K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 11 ·
Replies
11
Views
10K
  • · Replies 55 ·
2
Replies
55
Views
7K
Replies
15
Views
9K