Question

what is meant by real numbers?

Answer 1

Hoot! You just asked your first question! Hang tight while I find people to answer it for you. You can thank people who give you good answers by clicking the 'Good Answer' button on the right!

Answer 2

Do you know limits?

Answer 3

The field of all rational and irrational numbers is called the real numbers

Answer 4

Can you explain irrational numbers other than saying they are the non-rational real numbers?

Answer 5

an irrational number is any real number which cannot be expressed as a fraction a/b...

Answer 6

Yeah, that does not explain, what real numbers are!

Answer 7

so u understand wt an irrational no is

Answer 8

I'm just saying, that the original question was, what a real number is, and you can't explain it by saying "A real number is a real number (which is rational or not).". But it seems sarav is not interested anymore.

Answer 9

if u do knw wt a rational and irrational no is...then it is quite simple to understand wt real no is.. then the question is do u knw wt a rational or irrational no is

Answer 10

That was the other point a made: You can not know what irrational numbers are, until you know what real numbers are. So there is no use in bringing them up when explaining real numbers in turn!

Answer 11

A real number is a number that holds a position on a number line from negative infinity to poitive infinity

Answer 12

actually this is a very deep question, and not at all easy to understand. if you are asking "what does my teacher mean when referring to real numbers? then it is pest thought of a points on a number line

Answer 13

if you are asking what "mathemeticians" mean when they talk about "the real numbers" then there is a lot to be said and learned.
see for example
http://en.wikipedia.org/wiki/Real_number

Answer 14

this question is used to trip up graduate students on oral exams. it is very hard to answer.

Answer 15

you can research dedikind cuts if you have the patience
\ http://en.wikipedia.org/wiki/Dedekind_cut

Answer 16

I'm not sure that questions are posed to trip up students it sort of implies the examining body wants the student to fail.

Answer 17

satellite73: That's why I asked the inquirer whether she understands limits, because otherwise you don't need to know the difference between real and rational numbers.

Answer 18

but if you are asking because you hear people say "real number" it is a synonym for "all numbers" and you can think of points along a number line.

Answer 19

gianfranco, i am sure of it.

Answer 20

Ok i respect your opinion.

Answer 21

a real number is a number that exists. it can be an integer, decimal, rational or irrational number.

Answer 22

I don't know a way to define "exists" other than saying, a line of that length can be constructed just with compass and straight-edge. Even if you allow other units, like length of curved lines, I'm quite sure not all real numbers can be constructed. Also this is a very impractical definition. In particular it makes it impossible to show that the real numbers are a complete topological space, which is what you really in mathematics.
Fortunately mathematics doesn't rely on philosophical definitions.