User Yassin Rany

7 votes

1 answer

7k views

absolute value of supremum is smaller than or equal to supremum of absolute values

asked Mar 23, 2017 at 17:54

6 votes

1 answer

139 views

Why not every integral is zero?

asked May 12, 2016 at 19:24

5 votes

2 answers

261 views

Proof of a statement about eigenvalues and eigenvectors.

asked Jun 5, 2016 at 13:39

5 votes

6 answers

7k views

Any $n \times n$ matrix $A$ can be written as $A = B + C$ with $B$ is symmetric and $C$ skew-symmetric.

asked Jun 7, 2016 at 17:06

5 votes

3 answers

238 views

How to integrate $\int_{-3}^3 (x^2-3)^{3} \,dx$ without expanding the polynomial?

asked Jun 8, 2016 at 12:39

4 votes

2 answers

240 views

How to show that the set of all $(x,y)$ such that $3x^2 + 2y^2<6$ is an open set.

asked Jul 2, 2016 at 19:24

4 votes

2 answers

10k views

Is the interior of the closure of a set equal to the interior of that set?

asked Sep 4, 2016 at 12:05

4 votes

2 answers

685 views

The empty and full sets need to be in the topology of a set?

asked Oct 28, 2016 at 19:48

3 votes

1 answer

106 views

What is the image of the linear mapping ${P} : \mathbb{V}\rightarrow \mathbb{V}$ where $(Pf)(x)= [f(x) + f(-x)]/2$

asked Jun 7, 2016 at 15:00

3 votes

1 answer

160 views

How to integrate $\int{1\over \sqrt{x^2-1}}\mathrm d x$ another technique without use trigonometry

asked May 31, 2016 at 10:37

2 votes

3 answers

104 views

How to find $\lim_\limits{x\to0}(x \sin x)^{\tan x}$?

asked Jun 1, 2016 at 0:18

2 votes

3 answers

99 views

The limit of $f(x,y)= \dfrac {x^2 y}{x^2 + y^2}$ as $ (x,y) \to (0,0)$

asked Jul 4, 2016 at 16:01

2 votes

1 answer

65 views

Proof verification about inverses of linear mappings.

asked Jun 30, 2016 at 15:39

2 votes

1 answer

1k views

Proof that no natural number can be subset of any of its elements.

asked Aug 18, 2016 at 12:55

1 vote

2 answers

91 views

In $\mathbb R^n$ with usual topology (euclidean metric), exists a bounded open set $A$ such that $A$ is different from the interior of its closure?

asked Jun 1, 2017 at 1:18

1 vote

3 answers

80 views

If $p \to q$ and if $r \to s$, can we say that if $p \land r$ then $q \land s$?

asked Oct 29, 2016 at 18:47

1 vote

3 answers

618 views

About proof of theorem on topology

asked Dec 11, 2016 at 12:01

1 vote

1 answer

57 views

On Linear spaces: is the product of a scalar by a linear combination equal the l.c of same vectors with each scarlar multiplied by the first one?

asked Mar 13, 2017 at 19:15

1 vote

1 answer

83 views

About Implicit Functions

asked Oct 13, 2016 at 23:43

1 vote

1 answer

78 views

How to integrate $\frac{dx}{(x^2+k^2)^m}$, with $m$ positive integer.

asked May 28, 2016 at 12:26

1 vote

1 answer

163 views

Naive set theory really need axiom of power?

asked May 13, 2016 at 2:07

0 votes

0 answers

60 views

Why the image of a square under specific linear mapping is different if we define the square in two different ways?

asked May 19, 2016 at 20:43

0 votes

1 answer

36 views

how to find all values satisfing a function whose depends on another function?

asked May 24, 2016 at 21:01

0 votes

1 answer

30 views

How to proof that the set of all $X$ such that $X.A{\ge} c$ to some real number c is convex?

asked Jun 5, 2016 at 12:24

0 votes

1 answer

37 views

How to prove that a diference between the same component of two vectors is less than or equal to the norm of the vector diference?

asked Jul 1, 2016 at 12:55

0 votes

2 answers

74 views

Why the set of points satisfying (2x-x²-y²)*(x²+y²-x)>0 is the same of the set with condition ((2x-x²-y²)>o and (x²+y²-x)>0)?

asked Jul 7, 2016 at 22:55

0 votes

1 answer

41 views

How can i proof that every high order derivative of $\frac{1}{1+x}$ is equal to$ (-1)^kk!$ at point $0$.

asked Jun 26, 2016 at 13:32

0 votes

1 answer

184 views

About theorems on nowhere dense set

asked Oct 23, 2016 at 11:46

0 votes

1 answer

87 views

What do with Rieman-Stieltjes integral on an interval of a function with infinitely mane discontinuity points?

asked Sep 9, 2016 at 20:30

0 votes

1 answer

30 views

Could a scalar field $g(x,y)=0$ does not define implicitly neither $x$ nor $y$?

asked Oct 13, 2016 at 12:15

Stack Exchange Network

33 Questions

absolute value of supremum is smaller than or equal to supremum of absolute values

Why not every integral is zero?

Proof of a statement about eigenvalues and eigenvectors.

Any $n \times n$ matrix $A$ can be written as $A = B + C$ with $B$ is symmetric and $C$ skew-symmetric.

How to integrate $\int_{-3}^3 (x^2-3)^{3} \,dx$ without expanding the polynomial?

How to show that the set of all $(x,y)$ such that $3x^2 + 2y^2<6$ is an open set.

Is the interior of the closure of a set equal to the interior of that set?

The empty and full sets need to be in the topology of a set?

What is the image of the linear mapping ${P} : \mathbb{V}\rightarrow \mathbb{V}$ where $(Pf)(x)= [f(x) + f(-x)]/2$

How to integrate $\int{1\over \sqrt{x^2-1}}\mathrm d x$ another technique without use trigonometry

How to find $\lim_\limits{x\to0}(x \sin x)^{\tan x}$?

The limit of $f(x,y)= \dfrac {x^2 y}{x^2 + y^2}$ as $ (x,y) \to (0,0)$

Proof verification about inverses of linear mappings.

Proof that no natural number can be subset of any of its elements.

In $\mathbb R^n$ with usual topology (euclidean metric), exists a bounded open set $A$ such that $A$ is different from the interior of its closure?

If $p \to q$ and if $r \to s$, can we say that if $p \land r$ then $q \land s$?

About proof of theorem on topology

On Linear spaces: is the product of a scalar by a linear combination equal the l.c of same vectors with each scarlar multiplied by the first one?

About Implicit Functions

How to integrate $\frac{dx}{(x^2+k^2)^m}$, with $m$ positive integer.

Naive set theory really need axiom of power?

Why the image of a square under specific linear mapping is different if we define the square in two different ways?

how to find all values satisfing a function whose depends on another function?

How to proof that the set of all $X$ such that $X.A{\ge} c$ to some real number c is convex?

How to prove that a diference between the same component of two vectors is less than or equal to the norm of the vector diference?

Why the set of points satisfying (2x-x²-y²)*(x²+y²-x)>0 is the same of the set with condition ((2x-x²-y²)>o and (x²+y²-x)>0)?

How can i proof that every high order derivative of $\frac{1}{1+x}$ is equal to$ (-1)^kk!$ at point $0$.

About theorems on nowhere dense set

What do with Rieman-Stieltjes integral on an interval of a function with infinitely mane discontinuity points?

Could a scalar field $g(x,y)=0$ does not define implicitly neither $x$ nor $y$?