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6h
comment sin(n) is dense in [-1,1]
@user136266 Let $\theta=\arcsin(a)$....
19h
answered Prove a simple connected graph with n nodes and at least n edges has a cycle.
20h
comment Prove a simple connected graph with n nodes and at least n edges has a cycle.
Did you cover trees yet?
20h
awarded  Nice Answer
1d
comment Find the value of $a$ if the distance between $(3,-2)$ and $(4,a)$ is $\sqrt{7}$
The equation you have to solve already comes as $(a+2)^2+1=7$... There is no need for quadratic formula ;)
1d
comment Is it necessary that every function is a derivative of some function?
@Herbert This is also the characteristic function of the rationals, and it would not surprise me if it has another 4-5 names ;)
1d
answered Is it necessary that every function is a derivative of some function?
Apr
13
comment Can we find an element of infinite order in a symmetric group of infinite order?
@Danny If $A,B$ are any sets and $f: A \to B$ is a bijection, then $\sigma \in S_A$ and $f \circ \sigma \circ f^{-1}$ have the same order.
Apr
13
answered Can we find an element of infinite order in a symmetric group of infinite order?
Apr
12
revised Edge-Connectivity of a graph
added 126 characters in body
Apr
12
answered Edge-Connectivity of a graph
Apr
11
comment What are elements of a field called
@alex.jordan By definition "number" means an element in the field... But both are fields... So is a number in that situation a vector or a scalar? Note, that the issue appears when you start saying: Let $x$ be a number.... And even worse, what if you look at $\mathbb Q$ as a vector space over $\mathbb Q$? Yes, I know it is trivial but still....
Apr
11
comment What are elements of a field called
The first chapter, where the definition is, is about vector spaces. In many situations in algebra, the vector space has some field/ring structure, which might be ignored in that situation. It would be wrong to say "Let $x$ be a number" then.
Apr
11
comment What are elements of a field called
@alex.jordan Consider $K$ subfield of $L$. Then $L$ is a vector field over $K$.. Which are the numbers?
Apr
9
comment Is it possible to prove the existence of an integer with given order while not finding the value itself?
@orb If $x^2=1 \pmod{249}$ then the order is at most 2...But the order is 4...
Apr
9
answered Is it possible to prove the existence of an integer with given order while not finding the value itself?
Apr
9
answered Why does $\prod_{n=1}^\infty \frac{n^3 + n^2 + n}{n^3 + 1}$ diverge?
Apr
8
answered Prove that if Rank$(A)=n$, then Rank$(AB)=$Rank$(B)$
Apr
5
awarded  Yearling
Apr
3
answered Demonstrate that $\displaystyle \frac{(2n - 2)!!}{(2n - 3)!!} \simeq 1.7 \sqrt{n}$