[TUHS] The most surprising Unix programs
Juergen Nickelsen
ni at w21.org
Mon Sep 14 01:44:57 AEST 2020
Grant Taylor via TUHS <tuhs at minnie.tuhs.org> writes:
> For example, let's start with Pythagorean Theorem
>
> a² + b² = c²
[...]
> [a] [enter]
> [a] [enter]
> [multiply]
> [b] [enter]
> [b] [enter]
> [multiply]
> [add]
> [square root] # to solve for c
I do
[a] [square]
[b] [square]
[plus]
[square root]
6 keys. (Many operations push the entered value into the x register
without needing the enter key. Also, like with infix calculators,
usually there is a [x^2] key -- in postfix notation on both!)
> [a]
> [square]
> [plus]
> [b]
> [square]
> [square root]
That would give you the value of [b] and leave some rest of the
operation in the (hidden) registers. Actually you need
[a] [square]
[plus]
[b] [square]
[=]
[square root]
7 keys.
Although I started with infix calculators, I find it easier to work
my way out of more complex nested formulas with RPN than to track
the level of parentheses in my mind. Consider something like this:
3y * x / (z + 4k)^2 2w + v! \
------ * | ---------- + ---------- |
5b + z \ 3b * 4x ln(x + 2y) /
Now this is a PITA either way, but it comes easier for me with RPN.
[Sorry for the late reply -- I subscribed to TUHS earlier this year
and am only now making my way through it.]
--
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haben, was die Welt im Internet anbietet, die Fantasie-Sicherungen
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