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11

21

votes

7

answers

940

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A closed form for: $\int_{0}^{\infty} \frac{1}{(x-\log x)^2}dx$

Sep 9 '19 at 10:57 Community♦ 1

12

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Solving $ax^3+bx^2+cx+d=0$ using a substitution different from Vieta's?

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A $5\times 5$ grid of single-digit numbers in $\mathbb N$, with one cell empty. What number should be in the cell?

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Apr 6 '18 at 11:50 Community♦ 1

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In mathematics, is there a theory that deals with the distribution of numbers?

sequences-and-series number-theory natural-numbers

Mar 11 '18 at 9:24 Community♦ 1

4

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200

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Is this notation correct? $\sqrt {-25}=±5i$

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Feb 21 '18 at 13:33 Community♦ 1

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310

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Concept of undecidability and the Collatz problem [duplicate]

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3

votes

2

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622

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What is currently the highest lower bound for the length of a nontrivial cycle in the Collatz Conjecture?

soft-question collatz-conjecture open-problem

Mar 8 '19 at 17:10 rukhin 176

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3

votes

1

answer

70

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Where should I start to solve this problem?

calculus limits functions

Mar 1 '18 at 9:36 Lorenzo B. 2,162

3

2

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1

answer

75

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A Pythagorean quadruple-like equation: $(2a^2)^2+(ab)^2+2^2=c^2$

number-theory elementary-number-theory algebraic-number-theory diophantine-equations

Oct 2 '19 at 21:45 Maximilian Janisch 9,849

2

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1

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181

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What is the method to solve this system of equations?

algebra-precalculus algebraic-geometry polynomials systems-of-equations problem-solving

Sep 13 '19 at 8:36 Community♦ 1

2

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Is there an exact solution for $y'(x) = -\frac 15 y(x) (y''(x) + 1)$?

calculus ordinary-differential-equations closed-form

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2

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1

answer

186

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Are these statements always true?

sequences-and-series logic soft-question recurrence-relations closed-form

Apr 7 '19 at 13:29 Community♦ 1

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2

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Is there a substitute that will eliminate terms of the degree $3$ and $2$ from the quartic polynomial?

algebra-precalculus polynomials substitution quartic-equations

Sep 10 '19 at 23:19 Learner 710

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2

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Sep 9 '19 at 9:44 Dietrich Burde 105k

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3

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126

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Why doesn't the substitution $x=it$ work in the integral $\int\frac{x^2}{{(x^2+1)}^2}dx$?

calculus integration proof-verification indefinite-integrals

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1

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1

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70

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Prove that: If $a+b$ and $b$ are irrational, then $a+kb$ is irrational.

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May 8 '19 at 22:40 Community♦ 1

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answer

78

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Which one is the correct notation?

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Apr 21 '19 at 8:40 Community♦ 1

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1

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52

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In Mathematics, is there a multivariable graphic?

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Mar 4 '18 at 10:09 Learner 710

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1

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Can the infinite number of union of infinitely countable sets be an infinitely uncountable set?

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Mar 30 '19 at 20:29 Learner 710

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Why $\lim_{n\to \infty} \left(1+ \frac 1n \right)^n=e$ doesn't imply $\lim_{n\to \infty} \left(1+\frac 1n \right)≠1?$ [duplicate]

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Is it possible to find all values of $k$, like a function $k=f(m)?$

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26 Questions

A closed form for: $\int_{0}^{\infty} \frac{1}{(x-\log x)^2}dx$

Solving $ax^3+bx^2+cx+d=0$ using a substitution different from Vieta's?

A $5\times 5$ grid of single-digit numbers in $\mathbb N$, with one cell empty. What number should be in the cell?

In mathematics, is there a theory that deals with the distribution of numbers?

Is this notation correct? $\sqrt {-25}=±5i$

Concept of undecidability and the Collatz problem [duplicate]

What is currently the highest lower bound for the length of a nontrivial cycle in the Collatz Conjecture?

Where should I start to solve this problem?

A Pythagorean quadruple-like equation: $(2a^2)^2+(ab)^2+2^2=c^2$

What is the method to solve this system of equations?

Is there an exact solution for $y'(x) = -\frac 15 y(x) (y''(x) + 1)$?

Are these statements always true?

Is there a substitute that will eliminate terms of the degree $3$ and $2$ from the quartic polynomial?

A solution for nonlinear multivariable system of equation

Why doesn't the substitution $x=it$ work in the integral $\int\frac{x^2}{{(x^2+1)}^2}dx$?

Prove that: If $a+b$ and $b$ are irrational, then $a+kb$ is irrational.

Which one is the correct notation?

In Mathematics, is there a multivariable graphic?

Which square should be cut to minimize loss?

Can the infinite number of union of infinitely countable sets be an infinitely uncountable set?

"What is the specific mathematical reason behind the origin of the Collatz Conjecture that makes it difficult to solve it? [closed]

Why $\lim_{n\to \infty} \left(1+ \frac 1n \right)^n=e$ doesn't imply $\lim_{n\to \infty} \left(1+\frac 1n \right)≠1?$ [duplicate]

How can I solve $2x+\sqrt {10} \equiv 10 \pmod{13}?$

How is the expression “$a\equiv b \mod n$” pronounced?

Is it possible to find all values of $k$, like a function $k=f(m)?$

Is it possible to find $f(n)$? [closed]