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Comment: Re:Not exactly needed (Score 1) 62

by atomicdragon (#47260263) Attached to: A Seriously High Speed Video Camera (Video)
That requires gating the camera on the nanosecond time scale, which is many orders of magnitude away from something like this and a whole different technology. Most work with such cameras are limited to actually very slow frame rates (e.g. 60 Hz) but with a very fast shutter. The speed of such cameras is improving, and there is some tech coming out that allows multiple frames at nanosecond to picosecond separation, but it would still be a burst situation where you take a couple dozen images then have to wait milliseconds or longer to do it again. Neat videos of light propagation using such methods typically involve taking thousands of identical sequences and stitching them back together.

Comment: Re:clear and present danger (Score 5, Insightful) 800

by atomicdragon (#42799435) Attached to: Leaked: Obama's Rules For Assassinating American Citizens

2. He is signing executive orders for gun control rather than letting Congress make laws.

You complain of people being delusional and yet make such a stupid mistake as this. Which executive order and which action within controls guns? He's issued orders telling people to review polices and internals rules, to discuss and analyze the implications of various things and to share information or promote something. None of that is overriding Congress's laws or creating laws or new gun control without Congress. To be so disconnected from reality, you expect others to listen to what you say and trust your judgement of others' grip on reality?

Comment: Re:Choice (Score 3, Informative) 370

by atomicdragon (#42490863) Attached to: Forbes 2013 Career List Flamed By University Professors

Now, teaching 3 or 4 classes a semester may not be "relaxing," but it is less than 15 contact hours per week. Once you've taught the classes a couple of times, got the powerpoints made and the lectures down, that doesn't have to be very stressful. Be a good performer, put on a good show/lecture, and you'll get tenure.

What universities and fields offer tenure positions for just instructing 3 to 4 classes a semester? At the places I've worked, you would get maybe $2-3k per course you instructed, with no guarantee you would be rehired the next semester. As more tenure track professors retired, the number of people being paid as instructors like this has grown to the point of being the majority of how course instructors are paid at some places. To get tenure, you had to climb the ladder several years of successfully pulling in grant money and getting recognized for research, while hoping that there would still be a possible tenure position when you get that instead of some budget freeze preventing it, or the department deciding they want use the few tenure options on a different subfield, so as to not even give you a chance.

Comment: Re:This is just faulty math (Score 1) 1260

by atomicdragon (#33896086) Attached to: Proving 0.999... Is Equal To 1

This works in any simple base using the same concept of decimal representation.

In base x, consider the number zero followed by n digits of (x-1) after the decimal point, e.g. 0.FF...F with n Fs for hexadecimal. One minus this number gives the difference 1/x^n. In the limit n goes to infinity, this difference goes to zero for real numbers. And with the real numbers, zero difference means they are the same number.

Comment: Re:This is just faulty math (Score 1) 1260

by atomicdragon (#33895814) Attached to: Proving 0.999... Is Equal To 1

you have only ever done math with an approximation of pi.

This is only true if you define limit "math" to mean arithmetic and what simple calculators do. Algebra gives the abstract tools to work with numbers without needing the decimal expansion. By trigonometry and especially calculus, pi gets used a lot in an exact sense. Although sometimes the fundamental basis of what it means to work with an real numbers doesn't get covered until a course on real analysis.

Comment: Re:This is just faulty math (Score 1) 1260

by atomicdragon (#33895710) Attached to: Proving 0.999... Is Equal To 1

Mathematical proofs are a way of finding new properties of a system by making deductions from previously known properties, and in a practical sense are often a short-cut finding, the new property without testing every possible case.

For a simple example, consider the property that every integer multiplied by by 10 will end up with a zero in the ones place. Someone could respond: "How could you know that? There are an infinite number of integers and it would take infinite amount of time to multiply each by 10 to check it." But using a proof can rigorously show this is a pattern without testing every number by exploiting the properties of numbers.

In the case of multiplying 0.999... you can workout what the pattern any given digit will follow, and use that instead of manually performing the calculation.

"I've seen the forgeries I've sent out." -- John F. Haugh II (jfh@rpp386.Dallas.TX.US), about forging net news articles

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