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Messages - martinot

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Other Calculators / Re: Why RPN?
« on: February 24, 2018, 11:15:53 am »
Quote from: Xeda112358 on February 24, 2018, 10:31:47 am
Being older and wiser than I was in my last response, I maintain that RPN is the clear winner for performance, especially in an interpreted programming language, but infix is better for organization for humans.

Also @martinot, please edit your post instead of double posting.

I think it depends. Chain logic infix (as in four bangers or old calculators) is not always consequent and easy to use for some calculations.

If you do more advanced, or simpler calculations, it could be easier (and faster) with RPN, but I do agree that it needs to be understood first (not natural for a beginner).

I think that text book algebraic notation is probably the easiset entry for most people who is not accustomed to calculatots, but accustomed to mathematics.

Yes, I merged the comments to the first post, but could not find the ”delete”-button? Hade to empty the second post (or put in a ”.” as empty post was not allowed).

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Other Calculators / Re: Why RPN?
« on: February 24, 2018, 09:47:23 am »
An expression like 1/2x is interpreted as 1/(2x) by TI-82, but as (1/2)x by TI-83.

There can be ambiguity in the use of the slash symbol / in expressions such as 1/2x. If one rewrites this expression as 1 ÷ 2x and then interprets the division symbol as indicating multiplication by the reciprocal, this becomes: 1 ÷ 2 × x = 1 × ½ × x = ½ × x.

With this interpretation 1 ÷ 2x is equal to (1 ÷ 2)x. However, in some of the academic literature, multiplication denoted by juxtaposition (also known as implied multiplication) is interpreted as having higher precedence than division, so that 1 ÷ 2x equals 1 ÷ (2x), not (1 ÷ 2)x.

For example, the manuscript submission instructions for the Physical Review journals state that multiplication is of higher precedence than division with a slash, and this is also the convention observed in prominent physics textbooks such as the Course of Theoretical Physics by Landau and Lifshitz and the Feynman Lectures on Physics.

For this reason I agree that pure chain mode infix, RPN and text book algebraic entry on calculators/apps are much more defind and clear.

With ”command mode algebraic” entry you never know exactly what you will get.

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