Regarding matematical notation.
J is too rich for beginners.
We first learn addition, subtraction, multiplication and division. Later we use
the minus sign for negative numbers, like -2. Then we do not need subtraction
any more. The difference is written 7+-2, This was not taught in school.
Calculations are easier when avoiding subtraction:
(a+-b)^2 = (a+-b)(a+-b) = aa+a-b+-ba+-b-b = a^2+b^2-2ab.
Note that a-b is now the product (a)(-)(b) = -ab. You should normally write -ab
rather than a-b in order not to confuse your reader. The difference is written
a+-b.
Of course (-)=-1, or simply -=-1.
Then we learned about exponentiation. a^b.
The power a^- is the reciprocal to a. Formulas need no more contain fraction
bars. We may forget about division.
The power 2^- is one half, and a^2^- is the square root. Formulas need no
more contain root signs.
Multiplication signs are usually omitted, but 23 means twenty three rather than
two times three. Write the product 2^1 3^1 to avoid confusion. Then the
multiplication sign is no longer needed.
These simplifications make elementary formulas nicer.
In J you need not use the division and reciprocal sign (%), the square root
sign (%:), the subtraction (-),
/Bo
Den lørdag den 3. november 2018 08.02.42 CET skrev 'robert therriault' via
Chat <[email protected]>:
Mark Guzdial, a computer education researcher mentioned the Computer and
Mathematical Notation paper http://www.jsoftware.com/papers/camn.htm in his
blog
https://computinged.wordpress.com/2018/11/02/fixing-mathematical-notation-with-computing-and-proving-it-with-education/
Further he cited it as an example where success in changing mathematical
notation is measured by using the notation as a better way to educate students
and notes the books that Ken wrote using J to teach mathematics. I have been
surprised that more have not picked up this very important aspect of J.
Neat to see this turn up in the educational component of computer science.
Cheers, bob
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