Negar Rezaei Nejad's user avatar
Negar Rezaei Nejad's user avatar
Negar Rezaei Nejad's user avatar
Negar Rezaei Nejad
  • Member for 5 years, 3 months
  • Last seen more than a week ago
4 votes
1 answer
156 views

For which graphs we have domination number of (n-1)/2

2 votes
3 answers
274 views

Show that $g(x)=[\frac1x]\sin x$ has a limit in $x=0$.

2 votes
3 answers
72 views

If $f\colon [a,b] \to \mathbb{R}$ be continuous on $[a,b]$ Then there is a $ c \in [a,b] $ which have this equation for [closed]

2 votes
3 answers
126 views

Prove a combinatorics statement

2 votes
1 answer
257 views

How many four digit integer number exist that that the digits are either NOT in decreasing order or NOT in increasing order?(check my solution)

2 votes
1 answer
2k views

Prove this formula $1+\cos\theta+\cos2\theta+...+\cos n\theta=\frac{1}{2}+\frac{\sin(n+\frac{1}{2})\theta}{2\sin\frac{\theta}{2}}$ [duplicate]

2 votes
1 answer
88 views

Proof for $\frac{b}{h}=\frac{c(c-1)}{k(k-1)}$, a combinatorial identity

1 vote
2 answers
192 views

How many vertices with same degree

1 vote
1 answer
62 views

If n isn’t mth power of any natural number then prove $n^{\frac{1}{m}}$ is irrational [duplicate]

1 vote
2 answers
75 views

Prove $\sum_{d\mid n}\mu(d)=\lfloor \frac{1}{n}\rfloor$

1 vote
1 answer
370 views

$\sum_{d|n} \sigma(d)=\sum_{d|n} \frac{n}{d}\tau(d)$

1 vote
1 answer
70 views

Finding if $\sum_{n=1}^\infty\frac{n^n+1/n}{(n+1/n)^n}$ is convergent or divergent .

1 vote
1 answer
61 views

How many integer numbers with four distinct digits exist that they are either additive or reductive (check my answer)

1 vote
1 answer
1k views

Hamiltonian path exists if each two nonadjacent vertices has sum of degrees equal to n-1

1 vote
0 answers
213 views

Multiple of an Incidence matrix and its transpose

1 vote
1 answer
879 views

How many possible ways we can move a king in chessboard from 1A to 8H just using up right and diagonal move

1 vote
1 answer
51 views

Checking a proof about connected G and its connected complementary

0 votes
1 answer
127 views

Why does $\text{dim } \text{null} A = 1$ lead to the fact that solutions of $Ax=b$ are multiples of a nonzero solution?

0 votes
2 answers
1k views

Domination number of a path graph P(n)

0 votes
1 answer
47 views

For lambda eigenvalue of G , how to prove this statement

0 votes
2 answers
72 views

Using algebra to solve a graph problem

0 votes
3 answers
68 views

Prove $(n-1)^2 | (n^m-1) \iff (n-1)| m$. [duplicate]

0 votes
0 answers
58 views

Helping me understand an example from herstein’s book

0 votes
1 answer
62 views

If $(a,b)=1$ and $(\frac{a}{b})^m=n$ then show $b=1$ [duplicate]

0 votes
1 answer
174 views

prove that error order of backward euler method is $o(h)$

0 votes
4 answers
1k views

Solve this equation $(1+Z)^5=(1-Z)^5$

0 votes
1 answer
4k views

Check my answer for harmonic conjugate of $e^x Sin(y)$

0 votes
2 answers
131 views

Proof Möbius inversion theorem without using Dirichlet convolutions

0 votes
1 answer
161 views

find $\int_{0}^{1} x^2 e^x$ using trapezoidal rule with error less than $10^{-3}$

0 votes
0 answers
288 views

Why 1 isn’t $a*b=max(a,b)$ identity element?