Can someone prove (and explain step by step the proof) the density of Rationals in Real numbers?
By the way, in my notebook they gave the density of rationals in real numbers as definition, my second question is, definitions are things that we define and we can't prove them so why is there a proof? Maybe it's not a definition but a statement ? Or do definitions have proofs too? Thank you in advance.
I am puzzled as to what you are trying to say.
Prove what about density of the Rationals in the Real numbers? "The density of the Rationals in the Real numbers" is a noun phrase. We prove statements, not phrases.Can someone prove (and explain step by step the proof) the density of Rationals in Real numbers?
We define nouns, we prove statements. We might include some properties in the definition of a noun, rather than proving them. But, exactly what was this definition you are referring to? I know a definition of one set being "dense" in a superset, given some topology. Give such a definition, one would then have to prove that this definition applied to the rational numbers as a subset of the real numbers, given the usual topology.By the way, in my notebook they gave the density of rationals in real numbers as definition, my second question is, definitions are things that we define and we can't prove them so why is there a proof? Maybe it's not a definition but a statement ? Or do definitions have proofs too? Thank you in advance.
For example, we can say that any set, X, is "dense in the real numbers" if and only if, given any real number, y, and real number [itex]\lambda> 0[/tex], there exist a number, x, in X, such that [itex]|x- y|< \lambda[/itex]. We could then show, using that definition, that Q is dense in R.