Author Topic: A warning to engineers about calculators  (Read 8606 times)

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Online tggzzz

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Re: A warning to engineers about calculators
« Reply #125 on: December 20, 2024, 07:48:17 pm »
What does the colon in "8:2(2+2)" mean?
In context, I think it's just a placeholder for the classical divide operator symbol (instead of slash), whose unicode I do not recall.

Ah. Bizarre and unnecessary substitution.

Makes me think of the way Humpty Dumpty used the symbol "glory" (which was, of course, written by the mathematician Lewis Carroll).
ISO 80000-2 allows the use of the colon( : ) as ratio(a:b=0.375); the symbol ÷ should not be used. IIRC, the Greek, Latin and Arab arithmetic used colon( : ) as division sign, since fractional arithmetic was treated differently. Maybe the extended use of the fractional sign( /) should be considered bizarre and unnecessary substitution?

I wasn't aware of ISO80000-2, any more than most people are aware of ISO8601 for date formats (emphatically plural!) nor RFC5322 for email address specifications (not so many plurals) :)

I was taught ":" for ratio, and wouldn't use "/" for that.
Using "/" for a fraction is common, mainly due to limitations in earlier typing/printing technology.
Was ":" used to mean division before and/or after Robert Recorde invented the "=" equals sign in 1557 ? :)
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Offline TimFox

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Re: A warning to engineers about calculators
« Reply #126 on: December 20, 2024, 09:48:59 pm »
There is also the double ratio, or proportion as in  x:y :: s:t

The equals sign "=" was promoted since "no two things can be more equal", or
"And to auoide the tediouſe repetition of theſe woordes : is equalle to : I will ſette as I doe often in woorke vſe, a paire of paralleles, or Gemowe lines of one lengthe, thus: =, bicauſe noe .2. thynges, can be moare equalle."
 

Offline Zoli

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Re: A warning to engineers about calculators
« Reply #127 on: December 21, 2024, 02:24:21 am »
...
Was ":" used to mean division before and/or after Robert Recorde invented the "=" equals sign in 1557 ? :)
I've seen in physics textbooks(French, German and other languages) dated from the first half of the 20th century, about 45 to 50 years ago.
 

Offline SiliconWizard

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Re: A warning to engineers about calculators
« Reply #128 on: December 21, 2024, 02:45:03 am »
...
Was ":" used to mean division before and/or after Robert Recorde invented the "=" equals sign in 1557 ? :)
I've seen in physics textbooks(French, German and other languages) dated from the first half of the 20th century, about 45 to 50 years ago.

Yes. The division symbol ÷ was more commonly used though. But I'm guessing the simple colon : was used instead when the division symbol was not available as a character. So, basically a simplification of it.
 

Offline IanB

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Re: A warning to engineers about calculators
« Reply #129 on: December 21, 2024, 04:36:11 am »
Ratio and division are not the same. For example, 2:3 as a fraction is 2/5 or 2÷5.
 

Offline eugenenine

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Re: A warning to engineers about calculators
« Reply #130 on: December 31, 2024, 02:05:57 am »
Only one I ever use is droid48 and x48 on my laptop and pc. I use a rom dump from my own 48sx.
 
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Online tooki

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Re: A warning to engineers about calculators
« Reply #131 on: December 31, 2024, 10:24:10 am »
Well… one should use parentheses (not "brackets"--brackets are [ ] { }) …

US English:
() = parentheses
[] = brackets
{} = braces or curly brackets

UK English:
() = brackets
[] = square brackets
{} = curly brackets or braces

I don’t know which usage is common in other English speaking countries.
 


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