Let a and b be rational numbers. As always, prove your answers.
(a) For which choices...
Let a and b be rational numbers. As always, prove your answers.
(a) For which choices of a, b is there a rational number x such
that ax = b? (b) For which choices of a, b is there exactly one
rational number x such that ax = b?
Question 1. State the prove The Density Theorem for Rational Numbers.
Question 2. Prove that irrational numbers are dense in the set of real numbers.
Question 3. Prove that rational numbers are countable
Question 4. Prove that real numbers are uncountable
Question 5. Prove that square root of 2 is irrational
Question 1. State the prove The Density Theorem for Rational Numbers.
Question 2. Prove that irrational numbers are dense in the set of real numbers.
Question 3. Prove that rational numbers are countable
Question 4. Prove that real numbers are uncountable
Question 5. Prove that square root of 2 is irrational
PROOFS:
1. State the prove The Density Theorem for Rational Numbers
2. Prove that irrational numbers are dense in the set of real numbers
3. Prove that rational numbers are countable
4. Prove that real numbers are uncountable
5. Prove that square root of 2 is irrational
Prove that the rational numbers do not satisfy the least upper
bound axiom. In particular, if a subset (S) of the rational numbers
is bounded above and M is the set of all rational upper bounds of
S, then M may not have a least element.
Let A be an infinite set and let B ⊆ A be a subset. Prove:
(a) Assume A has a denumerable subset, show that A is equivalent
to a proper subset of A.
(b) Show that if A is denumerable and B is infinite then B is
equivalent to A.
Let A be a subset of all Real Numbers. Prove that A is closed
and bounded (I.e. compact) if and only if every sequence of numbers
from A has a subsequence that converges to a point in A.
Given it is an if and only if I know we need to do a forward and
backwards proof. For the backwards proof I was thinking of
approaching it via contrapositive, but I am having a hard time
writing the proof in...
Prove the following:
(a) Let A be a ring and B be a field. Let f : A → B be a
surjective homomorphism from A to B. Then ker(f) is a maximal
ideal.
(b) If A/J is a field, then J is a maximal ideal.
Let A = Z and let a, b ∈ A. Prove if the following binary
operations are (i) commutative, (2) if they are associative and (3)
if they have an identity (if the operations has an identity, give
the identity or show that the operation has no identity).
(a) (3 points) f(a, b) = a + b + 1
(b) (3 points) f(a, b) = a(b + 1)
(c) (3 points) f(a, b) = x2 + xy + y2