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| bio | website | code.google.com/p/notebk |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 1 year |
| seen | May 14 at 13:47 | |
| stats | profile views | 108 |
A mathematician, a programmer, etc. etc.
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Dec 2 |
comment |
Notation: What's $]a,b[$ This $]a,b[$ European notation (French, if I recall correctly) for the open interval $(a,b)$. It's sometimes still used in the literature, but I think parentheses carried the day. |
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Nov 30 |
answered | Using Octave to solve systems of two non-linear ODEs |
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Nov 25 |
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Showing $p(x,y) = \frac{d(x,y)}{1 + d(x,y)}$ is bounded by $1$ Well, first I'd use something other than $n$ for notation...but you can note $0\leq1/(1+n)\leq 1$ for all $n\geq0$, always, forever, in this or any other universe. That would prove (1). |
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Nov 24 |
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Equivalence of $a \rightarrow b$ and $\lnot a \vee b$ Also worth noting is, using De Morgan's laws, the expression for implication is equivalent to $\neg(p\land\neg q)$, which gives us some justification for proof by contradiction. I.e., if $p\land\neg q$ gives us a contradiction, its negation ($p\Longrightarrow q$) must be true. |
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Nov 24 |
revised |
About simplicial complex TeX-ed it up |
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Nov 24 |
suggested | suggested edit on About simplicial complex |
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Nov 24 |
awarded | Critic |
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Nov 24 |
revised |
How to prove a manifold is diffeomorphic to Euclidean space? TeX-ed it up... |
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Nov 24 |
suggested | suggested edit on How to prove a manifold is diffeomorphic to Euclidean space? |
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Nov 24 |
revised |
Derived Functors TeX-ed up the math |
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Nov 24 |
suggested | suggested edit on Derived Functors |
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Nov 23 |
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Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ @Limitless: thanks for the advice on typesetting :) I agree, having exactly one relational operator per equation is good; but once I got started, I just got too lazy to stop and sort it out :p |
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Nov 23 |
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Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ @robjohn: one day, I will remember arithmetic ;) Thanks! |
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Nov 23 |
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Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ added 5 characters in body |
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Nov 23 |
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Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ Exactly right! :) |
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Nov 23 |
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Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ Because the notation treats differentials like $\mathrm{d}x$ "as if" they were numbers, and could have $$\frac{\mathrm{d}y}{\color{red}{\mathrm{d}x}}\color{red}{\mathrm{d}x}$$ which is illegal mathematics. The result is right, the reasoning fallacious :( |
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Nov 23 |
answered | Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ |
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Nov 23 |
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Find $dy$ and evaluate $dy$ given $y=e^\frac{x}{10}$ , $x = 0$ and $dx = 0.1$ Well, it seems like you should recall $$ \mathrm{d}y=\frac{\mathrm{d}y}{\mathrm{d}x}\mathrm{d}x$$ From there, it should be straightforward to solve... |
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Nov 23 |
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How do I prove that $\mathbb CP^n$ is a 2n-manifold? Look at $g_{1}(z_2,\dots,z_n)=[1,z_2,\dots,z_n]$. Observe we can write it as $g_{1}(z)=[1,\mathrm{id}(z)]$. You can use the definition of continuity from analysis, using $\varepsilon-\delta$ proof taking $\delta=\varepsilon$ you have it immediately... |
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Nov 23 |
revised |
number of subgroups of $\mathbb{Z}_{5}\times\mathbb{Z}_{5}$ Used TeX... |
