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| bio | website | |
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| location | ||
| age | ||
| visits | member for | 1 year, 1 month |
| seen | 2 hours ago | |
| stats | profile views | 230 |
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Dec 15 |
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Find the coordinate matrix of the function $\cos^2x$ relative to the ordered basis $\{1,\cos x,\sin x,\sin 2x\}$. Since when are sets ordered? |
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Dec 12 |
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In a fraction between integers, what denominators produce a periodic result? Every ratio has periodic decimals, if that's what you're asking. |
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Dec 12 |
revised |
Defining the Complex numbers added 296 characters in body |
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Dec 12 |
answered | Defining the Complex numbers |
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Dec 11 |
answered | Show that that $|\sqrt{x}-\sqrt{y}| \le \sqrt{|x-y|}$ |
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Dec 11 |
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Mind Maps for teaching Mathematics mind maps are a waste of time in general. |
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Dec 11 |
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Another version of Heisenberg uncertainty principle It'd be very helpful if you could properly define all your variables. |
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Dec 11 |
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Does $\{f_ng_n\}\to fg$ uniformly? how can a sequence be unbounded and convergent under the natural topology? |
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Dec 10 |
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Relatively compact subset of open set in $\mathbb{R}^n$ Ugh, this is why I secretly hate mathematics. |
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Dec 10 |
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Relatively compact subset of open set in $\mathbb{R}^n$ @Cantor: if something is compact in $\mathbb{R}^n$, it is definitely compact in $U$. edit: ah yes, $\overline{A}$ math is simply not a subset of $U$ if it intersects the boundary. |
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Dec 10 |
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Relatively compact subset of open set in $\mathbb{R}^n$ Isn't $A$ relatively compact because it is bounded? Just apply Heine-Borel, or am I missing something? If the coordinates of elements of $A$ are bounded by $M$, then $\overline{A}$ is bounded by $2M$. |
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Dec 8 |
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Is $x^4+4$ an irreducible polynomial? @Sigur: no general one, because that would probably give you an efficient algorithm for prime factorization. |
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Dec 8 |
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Is $x^4+4$ an irreducible polynomial? @Sigur: sometimes you can use Eisenstein's criterion, but it is generally a hard problem. |
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Dec 4 |
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In Linear Algebra, why does the dimension of a vector space $\Bbb R ^ n $ equal $n$? And here, my dear friends, another reason why you should not attempt to learn math from Khan. |
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Dec 3 |
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The differentiability of $f(z)$ if $ \lim\limits_{z \to z_0} \frac {|f(z)-f(z_0)|}{|z-z_0|}=k$? "under additional regularity assumptions". |
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Dec 3 |
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Prime divisor in a finite group @Mathematics123: uh... Hagen just did... |
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Dec 3 |
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The differentiability of $f(z)$ if $ \lim\limits_{z \to z_0} \frac {|f(z)-f(z_0)|}{|z-z_0|}=k$? You did not prove that the angle is preserved. |
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Dec 3 |
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Prime divisor in a finite group @Mathematics123: there are groups for which your statement is true, and there are those for which it is false. |
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Dec 3 |
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Fields where $A^t=A$ and $A^t=-A$ I'm sorry, no, $F_2$ is the field of order 2, so just what you call $\mathbf{Z}_2$. |
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Dec 3 |
revised |
Fields where $A^t=A$ and $A^t=-A$ added 119 characters in body |
