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bio website linkedin.com/in/gt6989b
location New York, NY
age 36
visits member for 3 years, 4 months
seen 2 days ago

2d
comment Find the points where the function is continuous
Notice that $X$ is discrete. Let $x \in X$. What happens at $x$? What about at $x - \epsilon$ if you know $x -\epsilon \not \in X$?
Jan
26
comment Quickest way to determine a polynomial with positive integer coefficients
:-) A hi from one theoretician to another -- in theory beautiful but practically absolutely useless :-) +1
Jan
23
comment Quickest way to determine a polynomial with positive integer coefficients
I see the idea. But how would one practically determine the coefficients given the value on the output, especially in a computerized setting?
Jan
23
comment Quickest way to determine a polynomial with positive integer coefficients
I don't understand. Suppose you call the function and you now know $f(\pi) = 0$. What does that tell you about the coefficients or the degree of $f$?
Jan
20
comment Simple determinant in rectangular matrix
@Bobby see update...
Jan
13
comment One hundred indistinguishable ants are dropped on a hoop of diameter 1
awesome thanks veryt helpful
Jan
13
comment One hundred indistinguishable ants are dropped on a hoop of diameter 1
But why are the two problems (with bouncing and without boncing) equivalent? I agree if they don't bounce it is trivial, but why are the answers the same for both cases?
Jan
13
comment Graphing a Piecewise Function
i wonder why did someone downvote this... perfectly reasonable to ask a question with own solution posted...
Dec
30
comment Integration with absolute value
@rogerl thanks, fixed - confused sine and cosine
Dec
9
comment Evaluate $\int_{-\infty}^\infty \frac{1}{(x^2+1)^3} dx$
@dustin did not see the tag
Dec
9
comment Integrals over a Surface Using Stokes Theorem
What are your thoughts on the problem? Please explain what you tried and we will be happy to provide hints
Dec
9
comment Why is this true? (sum of 2 uniform distributions)
moved the comment into the answer for readability
Dec
8
comment Find a closed form for the generating function for each sequence below
Are these finite or infinite? (1) seems right to me...
Dec
8
comment Prove this relation
i am not saying this suffices to show that (3,5) is unique; i said, showing (3.5) is unique suffices to solve the problem, since we now can assume $y>0$...
Dec
8
comment Prove this relation
Another one is just as easy: since $y^2 \geq 0$, we must have $x>0$, and the problem is symmetric in $y$, i.e. if $(x,y)$ is a solution, then $(x,-y)$ is a solution as well. Hence, let's look for $y \geq 0$ and it suffices to show that $(3,5)$ is a unique solution.
Dec
8
comment Prove this relation
One observation is that $y$ is even if and only if $x$ is even, but if $y=2m,x=2n$ we have $4m^2+2 = 8n^3$, which happens if and only if $2m^2+1 = 4n^3$, which cannot be since LHS is odd while RHS is even. Hence, neither $x$ nor $y$ can be even...
Dec
8
comment Graph Theory triangle (3 colors)
I don't understand. If you properly edge-color $K_n$ with $n$ colors, no intersecting edges can have the same color, so any triangle must have distinct colors?
Dec
8
comment A good source for linear algebra on matrices
So you need something for abstract algebra with examples from linear algebra, or linear agebra theory, like vector spaces?
Dec
8
comment How can I rotate a point 45 degrees counterclockwise around any point?
@Nichols you are likely better off with $x' = x \cos \theta - y \sin \theta$
Dec
8
comment Finding Transformation inverse
@lllll this is only true about linear transformations from $\mathbb{R}^m$ to $\mathbb{R}^n$, you are transforming a function space.