Recent content by andrewcheong

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    Undergrad Standard Deviation in One Direction

    I need to calculate the average time of an event, and I'd like to calculate standard deviation as well. The problem is - there is no such thing as negative time - zero is a boundary - so how does it make sense if the average is 4000us (microseconds) and the stdev is 5000us? Is there a...
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    Heat Equation, Neumann, Fourier

    Hi, it's been a while since I touched mathematics and I'm a little rusty... I'm looking at a problem right now that I find difficult to understand, conceptually. Any insight would be greatly appreciated. (A direct solution would help immensely as well, not only because that's what I need to...
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    Graduate Distribution of Log of Random Variable

    Let X and Y be random variables. X ~ N(u,s^2) Y = r ln X, where r is a constant. What is the distribution of Y? (This is not a homework problem. It's just related to something I was curious about, and I can't figure out how to solve this, if it is solvable...)
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    Undergrad Optimizing Regression Degree with Weighted Cost Function

    Hello, all. I know what I want, but I just don't know what it's called. This has to do with regression (polynomial fits). Given a set of N (x,y) points, we can compute a regression of degree K. For example, we could have a hundred (x,y) points and compute a linear regression (degree 1). Of...
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    Graduate Is Centripetal Acceleration Relevant in Curved Space-Time?

    Hm, I'm not sure I understand how it is in freefall. I do understand the concept that the clock of the mover seems the same. What I'm trying to do is provide a more basic reason than exists today for why the clock of the mover and the clock of the observer ticks at different rates. There is...
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    Graduate Is Centripetal Acceleration Relevant in Curved Space-Time?

    I've taken Calculus I and Calculus II while in high school. We've done upto indefinite/definite integrals, etc. We did not get into integration in polar or parametric equations. We ended in some chapters concerning Taylor polynomials and expansions and such. I've also taken Physics I and...
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    Graduate Is Centripetal Acceleration Relevant in Curved Space-Time?

    I can't say I understand everything you said. I do know about the c limit and the addition of velocities. However, clearly, I do not know anything in this topic. I know of Mathematica, but I do not know it. I checked out your link (thank you) but I did not comprehend it at all. (I did...
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    Graduate Is Centripetal Acceleration Relevant in Curved Space-Time?

    This is the first thought that I had a question about, but it is highly dependent on a specific model of the universe, so I asked whether or not my model of the universe is feasible in a previous post, "Model of the Universe (I)". I have tried searching on Google for an answer, but I am not...