Vi Hart explains logarithms


Wait, didn’t we just hear she was quitting Youtube?

Just watched…brain is numb…burrs…

Girls, I know you will understand this and feel the intrinsic, incredible emotion
You have just pulled over your head the worn, warm sweater belonging to a boy…

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She rocks. Love this.

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Apparently these claims were baseless…


I always thought logarithms were what lumberjacks danced to.

Seriously, that explains why I punch “1000” into my calculator and press “log” and the answer comes back, “3”…guess my calculator thinks in base 10.

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This book was cooler:

Also, can anyone tell if those videos work not only as musings for the ones who already know what she’s talking about, but as actual learning videos as well?

Yes, log is usually base 10, ln is base e. Base 2 is useful too, but you have to figure it yourself.

The calculator thinks in base 2 but it’s smart enough to know that if you need to use a calculator your probably human, and if your human you probably think in base 10.

Finally doing math using a slide rule makes some kind of sense. The magic is gone… truth is revealed. Thanks logarithms, Thanks Vi!

Mathematicians reserve unadorned “log” for the natural logarithm, having little use for other bases. Scientists and engineers use “log” for base 10 and require “ln” for the natural log; “lg” is base 2, especially in computer science.

The decibel scale is logarithmic, defined as log base 10, but then multiplied by 10. Essentially this is base 10^(1/10) ~= 1.25892541179.

Suppose you have some calculator with a log key, but you don’t know what base it’s in – can you find the logarithm of x with respect to a particular base b? This is easy – just key in (log x)/(log b).

[/ log facts]

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Well, for me, someone for whom “log” was just a button on a calculator, I learned a lot. When she crosses out the letters at the end and writes in “log,” something magical happened, and I understood.

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I guess my engineering background shows. I have never seen “lg,” maybe it’s after my time.

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