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 May9 comment Your favourite maths puzzles I think this problem is a bit too well-known. en.wikipedia.org/wiki/Fair_coin#Fair_results_from_a_biased_coin May8 awarded Enlightened May8 awarded Nice Answer May8 comment Where did the word “logarithm” come from? @Qiaochu: Note that I was requiring that the word be accepted as "elevated" to lowercase usage in order to sufficiently divorce it from its origin as a proper noun. Both "algorithm" and (often) "abelian" enjoy this status. May8 accepted Need a result of Euler that is simple enough for a child to understand May8 revised Where did the word “logarithm” come from? added historical note May8 answered Where did the word “logarithm” come from? May7 answered Can this number theory MCQ be solved in 4 minutes? May7 comment Factorize $x^3-3x+2$ @cardano: since Jim didn't answer, I will: often you can notice small roots just from examination. For example, any polynomial with no constant term will have 0 as a root. If the sum of the coefficients sum to zero (as they do in your question) then 1 is a root. It's usually worth trying -1 as well. Most "real" polynomials won't have nice roots like this, but contrived homework problems and textbook problems will. May6 comment Infinity = -1 paradox A similarly wrong (but simpler) proof would go like this: $\infty+1$ is still $\infty$ since you can't make it any larger. But then we have $\infty = \infty+1$ and we subtract infinity from both sides proving $0=1$. May6 awarded Nice Answer May5 comment Factorize $x^3-3x+2$ I don't understand the animosity toward the asker here. What is wrong with asking how to factorize a polynomial? May4 answered Recommended Math knowledge for programming May3 comment Need a result of Euler that is simple enough for a child to understand @user9325: Only this [citation needed] wikipedia entry: en.wikipedia.org/wiki/Carl_Friedrich_Gauss#Family (The relevant portion of this entry is repeated hundreds of times in web searches, but none has a citation.) May3 awarded Nice Question May3 asked Need a result of Euler that is simple enough for a child to understand May3 awarded Enthusiast May2 awarded Self-Learner May2 answered Modulo arithmetic with big numbers? May1 comment Graph - finding cycles which contain specific edegs in O(|V| + |E|) (by DFS?) @Amir: I highly doubt that this level of detail was intended by the instructor who assigned this problem. Even in the case that $G$ is an adjacency list and $F$ is an unsort edge list, you can still get within the time bounds: simply convert the adjacency list to an adjacency matrix using $O(|V|+|E|)$ time (but $O(|V|^2)$ space!). Then your lookups are $O(1)$.