User q.Then

21 votes

4 answers

30k views

Proof that any linear system cannot have exactly 2 solutions.

asked Sep 16, 2015 at 21:40

12 votes

3 answers

3k views

mod Distributive Law, factoring $\!\!\bmod\!\!:$ $\ ab\bmod ac = a(b\bmod c)$

asked Dec 15, 2016 at 10:42

9 votes

1 answer

1k views

Collatz $4n+1$ rule?

asked Dec 7, 2015 at 3:17

5 votes

3 answers

3k views

Proof of no primes such that $x^2 + y^2 = z^2$ [duplicate]

asked Mar 9, 2015 at 16:48

4 votes

3 answers

218 views

How do I solve $18^{{20}^{19}}$ divided by 7?

asked Dec 15, 2016 at 9:59

4 votes

1 answer

3k views

If two finite groups have the same number of elements of the same order, does this necessarily imply they are isomorphic? [duplicate]

asked Nov 18, 2016 at 10:26

4 votes

2 answers

574 views

What is the precise definition of a group action that is a symmetry?

asked Nov 28, 2016 at 14:53

4 votes

2 answers

7k views

Finding the order of an element in the group of integers modulo n with addition

asked Sep 27, 2016 at 22:49

4 votes

3 answers

7k views

Prove existence of multiplicative inverse modulo p when p is prime

asked Oct 19, 2016 at 2:18

4 votes

1 answer

648 views

If $\omega$ is primitive nth root of unity, then does $|\text{Gal}(\mathbb{Q}(\omega)/\mathbb{Q})| = n - 1$?

asked Dec 9, 2017 at 7:51

3 votes

1 answer

644 views

Clarification on the Wronskian

asked Nov 9, 2016 at 7:39

3 votes

1 answer

59 views

Confused as to why $x^2 \equiv 1 \pmod p$ has at most 2 solutions when $p$ is an odd prime

asked Mar 16, 2017 at 6:48

2 votes

2 answers

315 views

If $a$ is a primitive root modulo $p$, then $(p-1) | ord(a)$ in $\mathbb{Z}/p^e\mathbb{Z}$

asked Apr 9, 2017 at 7:35

2 votes

1 answer

560 views

Proof that there are countable many algebraic numbers

asked Nov 16, 2016 at 6:05

2 votes

3 answers

12k views

How many elements of order 5 are there in $S_7$ [duplicate]

asked Oct 26, 2016 at 2:27

2 votes

2 answers

6k views

If Ax = 0 for every x in $R^n$, A is a zero matrix [duplicate]

asked Oct 15, 2015 at 23:32

2 votes

2 answers

193 views

How many arrangements can a team of 8 students have such at all of them have their birthdays in 2 days (but not all on one day)

asked Oct 1, 2015 at 7:18

2 votes

1 answer

671 views

How can I generalize this?

asked Feb 17, 2016 at 2:42

2 votes

1 answer

1k views

Definition of matrix norm induced by vector $p$-norm

asked Feb 27, 2016 at 22:22

1 vote

2 answers

35 views

Finding dimension mathematically for simple equations

asked Mar 16, 2016 at 23:36

1 vote

1 answer

1k views

How to find eigenvalues for T without given a matrix

asked Mar 18, 2016 at 2:59

1 vote

2 answers

498 views

Eigenvalues for $T = T^2$

asked Mar 18, 2016 at 14:56

1 vote

1 answer

363 views

Why does the additive inverse not follow

asked Feb 11, 2016 at 7:09

1 vote

3 answers

57 views

Justification for solving modular congruencies

asked Oct 18, 2016 at 4:07

1 vote

2 answers

295 views

What are the units of $\mathbb{R}[x]/\langle x^2 + 1\rangle$?

asked Dec 7, 2017 at 6:14

1 vote

1 answer

1k views

An algebraic simple extension has finite degree

asked Dec 8, 2017 at 22:12

0 votes

1 answer

588 views

How many automorphisms are there in $\mathbb{Z}_{105}$ of order $12$?

asked Dec 12, 2016 at 3:46

0 votes

1 answer

62 views

$3x + 1 = 2^i$ only has integer solutions when $i$ is even

asked May 9, 2016 at 18:50

0 votes

3 answers

97 views

For what values is $x + y = z$ and $a^x + a^y = a^z$?

asked May 10, 2016 at 20:38

0 votes

3 answers

47 views

Explanation on derivation of this equation?

asked Feb 12, 2016 at 6:25

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37 Questions

Proof that any linear system cannot have exactly 2 solutions.

mod Distributive Law, factoring $\!\!\bmod\!\!:$ $\ ab\bmod ac = a(b\bmod c)$

Collatz $4n+1$ rule?

Proof of no primes such that $x^2 + y^2 = z^2$ [duplicate]

How do I solve $18^{{20}^{19}}$ divided by 7?

If two finite groups have the same number of elements of the same order, does this necessarily imply they are isomorphic? [duplicate]

What is the precise definition of a group action that is a symmetry?

Finding the order of an element in the group of integers modulo n with addition

Prove existence of multiplicative inverse modulo p when p is prime

If $\omega$ is primitive nth root of unity, then does $|\text{Gal}(\mathbb{Q}(\omega)/\mathbb{Q})| = n - 1$?

Clarification on the Wronskian

Confused as to why $x^2 \equiv 1 \pmod p$ has at most 2 solutions when $p$ is an odd prime

If $a$ is a primitive root modulo $p$, then $(p-1) | ord(a)$ in $\mathbb{Z}/p^e\mathbb{Z}$

Proof that there are countable many algebraic numbers

How many elements of order 5 are there in $S_7$ [duplicate]

If Ax = 0 for every x in $R^n$, A is a zero matrix [duplicate]

How many arrangements can a team of 8 students have such at all of them have their birthdays in 2 days (but not all on one day)

How can I generalize this?

Definition of matrix norm induced by vector $p$-norm

Finding dimension mathematically for simple equations

How to find eigenvalues for T without given a matrix

Eigenvalues for $T = T^2$

Why does the additive inverse not follow

Justification for solving modular congruencies

What are the units of $\mathbb{R}[x]/\langle x^2 + 1\rangle$?

An algebraic simple extension has finite degree

How many automorphisms are there in $\mathbb{Z}_{105}$ of order $12$?

$3x + 1 = 2^i$ only has integer solutions when $i$ is even

For what values is $x + y = z$ and $a^x + a^y = a^z$?

Explanation on derivation of this equation?