Roberto Abraham Scaruffi

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Which mathematical conjecture turned theorem has very simple elementary proof but took more time to prove it? Alon Amit, Mathcircler and Origamist. 90 votes Here are a few well-known examples. The first two are covered in Aigner and Ziegler's wonderful "Proofs from the Book", where many other short and clever proofs are presented. The Sylvester-Gallai Theorem The claim is simple and rather intuitive: If you have some points in the plane, either they are all on the same line, or else there is a line that passes through exactly two of them. (By "... Read More » What startup investors have really bad reputations? Jason M. Lemkin, partner @ Storm Ventures; ceo/co-founder @ EchoSign (acq'd by Adobe), the web's #1 electronic signature service. 324 votes Having pitched over 150 VCs, taken money from a dozen across four start-ups (2 as a founder) ... and now having become a VC myself ... let me say this: All VC Funds Have Engaged in Some Arguably Questionable Behavior at Some Time -- From the (Non-Objective) Perspective of a Founder at least. [Probably all founders have done some arguably questionable behavior as well, but that's a different... Read More » Which is greater, [math]70^{71}[/math] or [math]71^{70}[/math]? Michal Forišek, teacher, scientist, competitive programmer 2.3k votes Here's how to make a quick estimate. Let's start by dividing the two numbers: [math]\frac{70^{71}}{71^{70}} = 70\cdot\left(\frac{70}{71}\right)^{70}= 70\cdot\left(1-\frac{1}{71}\right)^{70}[/math] Now, if you have a sufficient background, you should recognize that [math](1-1/(n+1))^n[/math] goes towards [math]1/e[/math] as [math]n[/math]goes towards infinity. For [math]n=70[/math] we will already be pretty close. Hence, not only do we know that [math]70^{71}[/math] is the greater of our two numbers, we can also estimate that their ratio is roughly [math]70/e \approx 26[/math]. What types of jobs are available for those that know just HTML/CSS and JavaScript? Marcus Geduld, Shakespearean director, computer programmer, teacher, writer, likes dinosaurs. 304 votes By being hired by companies that require front-end development. I don't only know JavaScript, CSS and HTML, but they're pretty much the only technologies I ever use at work, because there's so much front-end coding to do and so few other people on the team who know how to do it well. There are exceptions, but most of the server-side developers I know aren't JavaScript experts (and vice versa). ... Read More » As a non technical co-founder, I often find myself not knowing what to do while my product is being developed. What should I do? Axel Schultze, CEO Society3 - late stage accelerator and fundraising platform. S3-vc 561 votes You have only 24 hours a day minus 10 to sleep and eat makes it 14 hours. I assume you are tackling a large market and want to conquer the world. I also assume you want to have about 30% market share of whatever billion dollar market with roughly 20 Million potential customers. The 14 hour day of a startup CEO 1) List building 1 hour Start spending an hour a day to extend the list of potentia... Read More » Could someone with a below average IQ (e.g. under 80) earn a PhD (e.g. in mathematics) through hard work? Tom Mcneill, Ph.D. 413 votes I'm going to go against the grain here a bit. I went to school with a mathematics savant. Let's call him "Billy". Billy could do triple integrals in his head, but could barely tie his shoes. He had to have a roommate /care taker, who took care of him, made sure he ate, made sure he bathed, dressed himself, and so forth. The university put a special curriculum together for him that allowed ... Read More » What is the future of food delivery? Adam D'Angelo, Quora CEO 2.4k votes In the long term, only professional full-time cooks should be cooking and most people will likely get all their meals via delivery. Over the next few years, two trends dominate: Delivery networks like OrderAhead (disclosure: I'm an investor) and DoorDash get built out. If you're in a relatively dense area, it becomes easy to get food delivered from almost anywhere you want for the marginal cos...  Read More » How do I convince my daughter not to become a programmer like me? Mark VandeWettering, Technical Director 42 votes I understand your concern: nobody wants their daughter to be subjected to sexism and discrimination. And nobody can tell your daughter that she should subject herself to those potential ills to serve a higher purpose, like a more equal society. She is in no way obligated to pick up that cause as her own. But consider the following. Programming and software engineering can be a great, reward... Read More » What startup ideas sounded the best, but didn't work out? Robert Maynard, Founder, i-me. Co-founder LifeLock, Internet America. Two of three are public. 318 votes DotSafe - After Internet America, I saw yet another story about a local girl meeting a "friend" online who turned out to be a child molester and murderer. I had the skills, the team and the capital to make a difference, so I decided to build a "safe" Internet Service Provider. Everyone thought this was a great idea. I did focus groups in five cities before writing a line of code or hiring o... Read More » Were almost all professors exceptional as grad students? Vijay Pande, Professor at Stanford University, Director of the Folding@home Distributed Computing Project 560 votes At the top levels, generally professors have excelled at every stage. The people who shine the most in graduate school tend to get the best postdoctoral positions (especially the independent positions like Miller Fellow or Harvard Fellow) and those top postdocs tend to get the best faculty positions. While there are always exceptions, it’s rare that an unsuccessful graduate student comes ou... Read More »