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π = 3 (sometimes) for Nobel laureate

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Re: π = 3 (sometimes) for Nobel laureate

#11
post #9

Pi ~ 3, but we also often need Pi^2, which is better approximated as 10. (I actually got into an argument about rounding Pi^2 to 10 once with a person who liked to round Pi to 3 ...)

I remember using Pi^2 to be approximately g (the acceleration due to gravity near the earth's surface). This comes in real handy when simplifying the time period of a pendulum.

Re: π = 3 (sometimes) for Nobel laureate

#14
post #11
post #9

Pi ~ 3, but we also often need Pi^2, which is better approximated as 10. (I actually got into an argument about rounding Pi^2 to 10 once with a person who liked to round Pi to 3 ...)

I remember using Pi^2 to be approximately g (the acceleration due to gravity near the earth's surface). This comes in real handy when simplifying the time period of a pendulum.

Yep- and rounding g to 10 m/s^2 when there's no pi involved- so you can actually talk conversationally about free-fall because you can then do the math in your head.

Re: π = 3 (sometimes) for Nobel laureate

#15
post #13
post #12

It's a little unrelated, but if you ever need to know the number of seconds in a year, it's pi x 10^7 to within .5%.

Proof for the curious: http://www.google.com/search?q=number+of+seconds+in+a+year+d...

I understand what you did, but the mathematician in me cringed at the word "proof" in that comment.

Re: π = 3 (sometimes) for Nobel laureate

#16
post #3

This guy sounds like every microelectronics prof ever. :) I took that to heart when doing the exams and it make the impossible possible.

I really enjoyed it when my EE professors would simply erase components of a circuit diagram if they didn't matter and they made things complicated. I think that had an impact on my approach to solving problems.

Another trick of the trade is working back from the desired output by stages. For example, for an amplifier delivering 200 W to loudspeakers (or 1 kW to an antenna, or ...), first design the final stage, then work back from that adding the stages needed until the range is OK for the input signal you have.

Re: π = 3 (sometimes) for Nobel laureate

#17
I will never forget an high school assignment in physics in France, where we were asked to calculate how a wheel of a given diameters would put marks to the road if it had a pen attached at a given position.

Our teacher always said she accepted all result with an error of less than 10% if we did that by making the calculus easier.

So I started by "let's define pi=3"

I got a bad grade on that one, even after I protested that the answer was within the required specifications, so afterwards as a nag, I was always over-precise with her assignments - like always included electron mass in nucleus calculations :-)

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