4,346 reputation
11040
bio website sharif.academia.edu/…
location Tehran, Iran
age 25
visits member for 3 years, 7 months
seen 2 hours ago

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Aug
16
revised Length of a cycle
added 24 characters in body
Aug
16
reviewed Approve Normal distribution and algebra problem
Aug
16
comment Characterizing groups with linear subgroups
@user138171 $G$ cannot contain an element with infinite order.
Aug
16
answered Characterizing groups with linear subgroups
Aug
16
answered There is no group whose quotient by the center is isomorphic to the quaternion group
Aug
14
reviewed Approve True or False: The circumradius of a triangle is twice its inradius if and only if the triangle is equilateral.
Aug
14
comment If in a group $G$, we have $a^5 = e$ and $aba^{-1} = b^2$ for some $a$, $b$ in $G$, then what is the order of $b$?
@BabakS.lotf dari Babak jan. Thanks in advance.
Aug
13
awarded  Enlightened
Aug
13
awarded  Nice Answer
Aug
12
reviewed Approve Stable manifold for bidimensional nonlinear dynamic system with complex eigenvalues
Aug
12
reviewed Approve How find this maximum and minimum of the value $\sum_{i=1}^{n-1}[x_{i+1}-x_{i}]$
Aug
10
reviewed Approve Gaussian Elimination method with respect to maximum XOR subset problem?
Aug
10
reviewed Approve $X = (X_1, X_2)$ is it not a multivariate random variable?
Jul
31
reviewed Approve Produce unique number given two integers
Jul
29
comment Free product as automorphism group of graph
But I prefer introduction to group theory by Oleg Bogopolski. It is very readable, and I guarantee it.
Jul
29
comment Free product as automorphism group of graph
@user1729 I have not seen this book, but I think the literature of this book is little bit strange. Isn't it?
Jul
29
comment Free product as automorphism group of graph
@user1729 I think by symmetries, he means a subgroup of automorphism of tree such that preserves the color of each part(preserves bipartite structure).
Jul
29
comment Why $ (1- \sin \alpha + \cos \alpha)^2 = 2 (1 - \sin \alpha)(1+ \cos \alpha)$?
$2 (1 - \sin\alpha + \cos\alpha - \sin\alpha\cos\alpha)=2 (1 + \cos\alpha -\sin\alpha - \sin\alpha\cos\alpha)=2 (1 + \cos\alpha -\sin\alpha(1+\cos\alpha))$. I moved the position of sin and switched with cos.
Jul
29
comment Why $ (1- \sin \alpha + \cos \alpha)^2 = 2 (1 - \sin \alpha)(1+ \cos \alpha)$?
It is a common factorization. where is it exactly your problem?
Jul
16
reviewed Approve How to calculate gradient of $x^TAx$