Let A = {a+b*sqrt14: a,b∈Z}. Prove that A ∩ Q = Z. Explain is set A...

Let A = {a+b*sqrt14: a,b∈Z}. Prove that A ∩ Q = Z. Explain is set A countable?

Expert Solution

Colby Messinger answered 1 year ago

Let A be an infinite set and let B ⊆ A be a subset. Prove: (a)...

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 = Z and let a, b ∈ A. Prove if the following binary operations...

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

(a) Prove that Q(sqareroot 5)={a+b sqareroot 5 ; a,b in Z} is a subring of Z....

(a) Prove that Q(sqareroot 5)={a+b sqareroot 5 ; a,b in Z} is a subring of Z. (b) Show that Q(sqareroot 5) is a conmutative ring. (c) Show that Q(sqareroot 5) has a multiplicative identity. (d) show that Q(sqareroot 5) is a field.(Hint : you want to mulitply something by he conjugate.) (Abstract Algebra)

let n belongs to N and let a, b belong to Z. prove that a is...

let n belongs to N and let a, b belong to Z. prove that a is congruent to b, mod n, if and only if a and b have the same remainder when divided by n.

(A) Let a,b,c∈Z. Prove that if gcd(a,b)=1 and a∣bc, then a∣c. (B) Let p ≥ 2....

(A) Let a,b,c∈Z. Prove that if gcd(a,b)=1 and a∣bc, then a∣c. (B) Let p ≥ 2. Prove that if 2p−1 is prime, then p must also be prime. (Abstract Algebra)

Let G be a group. For each x ∈ G and a,b ∈ Z+ a) prove...

Let G be a group. For each x ∈ G and a,b ∈ Z+ a) prove that xa+b = xaxb b) prove that (xa)-1 = x-a c) establish part a) for arbitrary integers a and b in Z (positive, negative or zero)

Discrete Math Course. On Z, let B be the set of subsets A of Z where...

Discrete Math Course. On Z, let B be the set of subsets A of Z where either A is finite or A complement is finite. Define + and * as union and interception. Show whether or not B is a boolean algebra.

Let X be the set of equivalence classes. So X = {[(a,b)] : a ∈ Z,b...

Let X be the set of equivalence classes. So X = {[(a,b)] : a ∈ Z,b ∈ N} (recall that [(a,b)] = {(c,d) ∈Z×N : (a,b) ∼ (c,d)}). We deﬁne an addition and a multiplication on X as follows: [(a,b)] + [(c,d)] = [(ad + bc,bd)] and [(a,b)]·[(c,d)] = [(ac,bd)] Prove that this addition and multiplication is well-deﬁned on X.

Suppose A = {(a, b)| a, b ∈ Z} = Z × Z. Let R be...

Suppose A = {(a, b)| a, b ∈ Z} = Z × Z. Let R be the relation define on A where (a, b)R(c, d) means that 2 a + d = b + 2 c. a. Prove that R is an equivalence relation. b. Find the equivalence classes [(−1, 1)] and [(−4, −2)].

Let G be a group,a;b are elements of G and m;n are elements of Z. Prove...

Let G be a group,a;b are elements of G and m;n are elements of Z. Prove (a). (a^m)(a^n)=a^(m+n) (b). (a^m)^n=a^(mn)

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