1,220 reputation
317
bio website andrew-christianson.github.io
location Los Angeles, CA
age 23
visits member for 3 years
seen 13 hours ago

Jun
4
comment Ratio and number theory
@Kartik. Ah. I didn't know it was an exam problem. Marvis' answer is definitely the better solution then
Jun
3
revised Convolution correct?
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Jun
3
suggested suggested edit on Convolution correct?
Jun
3
comment Ratio and number theory
@Kartik I feel obliged to point out that this is problem where brute force can definitely prove the right answer. There are only 900 possible $K$s, so it is feasible to check each one to find the minimum.
Jun
3
comment Ratio and number theory
With positive division, floor is effectively a truncate function; it returns the integer part of a ratio. Lets take $x=152$ as an example. So let, $d_{100}(152)= \left\lfloor\frac{152}{100}\right\rfloor = \left\lfloor 1.52\right\rfloor = 1$ which is the hundreds digit. Then clearly, $\left\lfloor\frac{152-100*1}{10}\right\rfloor = 5$ is the tens digit, because we've subtracted off the hundreds. Just rephrase the $100*1$ to $100*d_{100}(152)$, and you've got a general expression for the tens digit. Repeat the same process for the 1s digit.
Jun
3
revised Ratio and number theory
Convert to Latex
Jun
3
suggested suggested edit on Ratio and number theory
Jun
3
answered Ratio and number theory
Jun
3
revised Ratio and number theory
edit for clarity
Jun
3
suggested suggested edit on Ratio and number theory
Jun
3
comment Tricky probability explanation
math.ucdavis.edu/~gravner/MAT135A/materials/…
Jun
3
revised Show that $F_X(q_t)=t$
Format, texify, edit for clarity.
Jun
3
suggested suggested edit on Show that $F_X(q_t)=t$
Jun
2
comment Draw a graph from an incidence matrix in Excel
The documentation I linked indicates it takes an incidence matrix. This isn't exactly my area though, so I can't attest to it. R is free though, and very effective so I'd give it a shot.
Jun
2
comment Draw a graph from an incidence matrix in Excel
Yup, looks like R will do it. I've added an answer with links to it and the necessary package.
Jun
2
comment Stochasticity of Fermi problems
Do you have a reference to where you've heard that description? It may be easier to explain if we had the specifics of that view available.
Jun
2
answered Draw a graph from an incidence matrix in Excel
Jun
2
comment Draw a graph from an incidence matrix in Excel
I can't offer specific software recommendations, but know that Excel can save files as comma separated value or tab delimited (.csv or .tab) files, which are pretty much universal for data-driven software. So, no need to limit your search only to programs that can read from excel files.
Jun
2
comment System of two Equations
@the-ever-kid Sorry, I was a little snarky. I thought you were contending your graph was correct because it was from mathematica and you thought mine was from gnuplot. I think we've both been reassured that tone does not always come through well on the internet.
Jun
1
comment System of two Equations
@the-ever-kid sorry, I got confused with the names. I'm not sure what you're getting at with your comment about gnuplot. Just because yours is from mathematica doesn't make it more right (mine was from Maple btw). Just to prove it to you though, here's the same implicit graph from the original system of equations from Mathematica: imgur.com/dPqq1 which you can draw yourself with: $$ContourPlot[{y + (x)^{(1/2)} == 11 , x + (y)^{(1/2)} == 7}, {x, 0, 10}, {y, 0, 10}]$$ also, wolframalpha: wolframalpha.com/input/…