Roberto Abraham Scaruffi

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Top Content For You This Week What are some interesting, lesser known uses of the quadratic formula? 2.2k Linus Hamilton (Courtesy of Razvan Gelca: Say we want to solve the cubic equation . ... Read More » How can I prove that 2^66 - 1 is not a prime number? 139 Dan Taylor, Master's degree in math To answer your more general question about the thought process/where to start on a proof consider this as an example: First, you need to know what the problem is asking yo... Read More » What is it like to sell your company to Google? 1.2k Sam Schillace Intense. Fun. Very hard. Scary. Sometimes frustrating. We showed up with four people. They gave us desks, ran us through orientations and more or less turned us loose. De... Read More » Let a, b be two real numbers. What is the probability that the leading digit of a/b is 1? 157 Anders Kaseorg, MIT 2008, S.B. in Mathematics with Co... The question is ill-specified, because you didn’t choose a probability distribution from which to sample . I am not just being pedantic here—there is no uniform distributio... Read More » Why didn't (or shall I dare say couldn't) academics working in the transportation and space areas come up with the ideas Elon Musk is coming up with? 427 Anirudh Joshi, When the facts change, I change my mi... You honestly think Musk came up with those ideas? Please. Tesla was founded by two other SV engineers who later brought Musk in as a financier. ... Read More » How has Jeremy Lin used his personal failures and mistakes to grow as a basketball player and as a person? 590 Jeremy Lin, Point Guard for the Houston Rockets Often times, failure makes me re-evaluate what I need to get better at, whether it is on the court or as a person. God has frequently turned my short comings and failures i... Read More » What is special about the normal distribution? 3 Yisong Yue, Machine Learning Researcher Essentially, the Gaussian distribution is the unique distribution that has zero k-th order central moments for all k>2 (i.e., the skew, kurtosis, etc. are all 0). The Centr... Read More » How necessary is the NASA program? How necessary is anything that was essentially borne out of showboating between nations? - Should we not be using that money instead on things that advance healthcare and decrease poverty? 378 Tanmay Mudholkar, Apprentice Physicist, Level 3 In 1970, a nun working in Africa asked the same question. Dr. Ernst Stuhlinger, a pioneer of rocket flight, sent her a letter in reply which I reproduce here. May 6, 1970...  Read More » What is most famous number series besides Fibonacci? 28 Yash Farooqui, 2012 and 2013 Mathcamper Clearly the Catalan numbers. Even if they are not the most famous other  sequence, they truly ought to be, for their combinatorial ubiquity and  use in computer science. H... Read More » What is the difference between the prior and the posterior in statistics? 48 Jack Rae, Quora Data Scientist Say you have a quantity of interest: . The prior is a probability distribution that represents your uncertainty over before you have sampled any data and attempted to est...  Read More »