Elliott
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 Oct11 asked When does $a + b$ divide $a^p + b^p$? Oct11 asked Why does $a^n - b^n$ never divide $a^n + b^n$? Aug29 awarded Good Question Aug29 comment What's the probability that a sequence of coin flips never has twice as many heads as tails? This solution is beautiful! One thing I don't understand is, how did you set boundary conditions for the region n >= 0? Aug27 comment What's the probability that a sequence of coin flips never has twice as many heads as tails? Wow, incredible (both the write up and the result itself)! However, I have a slight point of confusion--why is S(1) = 1, rather than 3? Aug27 comment What's the probability that a sequence of coin flips never has twice as many heads as tails? Sorry, I'm not sure I follow. Can you please explain what P(n) represents in slightly more detail? Aug27 awarded Nice Question Aug27 asked What's the probability that a sequence of coin flips never has twice as many heads as tails? Aug24 awarded Nice Question Aug22 awarded Enlightened Aug22 awarded Nice Answer Jul30 awarded Nice Question Jul10 comment Proving the countability of algebraic numbers An alternative approach to showing that polynomials with integer coefficients are countable: consider the bijection $\phi: \mathbb{Z}[x] \rightarrow \mathbb{N}$ that sends the polynomial $a_0 + a_1x + a_2x^2 + \ldots + a_nx^n$ to the natural number $2^{b_0}3^{b_1}5^{b_2}\cdots p_n^{b_n}$ (notation: $p_i$ is the $i$-th prime number and $b_i$ is the image of $a_i$ under any bijection from the integers to the natural numbers). Jul9 comment Motivating linear algebra for economics students? Why the -1? Anything I can do to improve this question? Jul9 asked Motivating linear algebra for economics students? Jul7 awarded Enlightened Jul5 awarded Populist Jun29 comment Is there a “good” way to visualize complex vectors? They are isomorphic as vector spaces over $\mathbb{R}$ only. But no, I was trying to figure out how you visualize 4 spatial dimensions in the first place. Jun28 comment Is there a “good” way to visualize complex vectors? How do you like to visualize $\mathbb{R}^4$? Jun24 comment Are “$n$ by $n$ matrices with rank $k$” an affine algebraic variety? Great answer, thank you! Regarding the definition, I agree with your disagreement; the book I'm reading explicitly says "this is only a temporary working definition" (the "real" definition to be given a bit later). Regarding the exercise, is there anything preventing me from taking the subspace spanned by the matrix with 1's in the first $k$ positions of the main diagonal? Finally, I'll try to get a handle on the geometric perspective in the meantime.