Teaching Approximations (was Re: Microcode, which is a no-go for

[Fred Cisin]

On Wed, 9 Jan 2019, Philip Belben via cctalk wrote:
> For me, the one that bugs me is sqr(3), which comes up in electrical 
> engineering a lot in 3-phase circuits.
> What bugs me is seeing people type "1.73" into their calculator when they 
> mean sqr(3).  I know other people disagree with me on this - some say it 
> doesn't matter, others say it shows the person is thinking about the problem 
> rather than just using a textbook formula - but here is my take.
> Firstly, I don't know about many modern calculators, but on the calculators I 
> grew up with, and on my HP-48, sqr(3) takes _fewer_ keypresses than 1.73, so 
> why would anyone want to type that?

except that not all calculators have sqrt key in same place, so sometimes 
it's quicker to just type the number.

> Secondly, how accurate is 1.73?  I am willing to bet these people don't know. 
> A more precise figure is 1.73205... so 1.73 is about 0.12% too small.

I have ALWAYS used 1.732   It is accuraate enough for any of my needs.
"But, how do you remember it?"
"Easy.  the year that George Washington was born."
"But how do you remember THAT?"
"Extremely easy!  Square root of 3 !"