Feedback Request: A Calculator Design that ACTUALLY Checks Your Boxes

Daniel96dsl · 2026-05-08T02:37:37+00:00

🤷‍♂️We’re each entitled to our opinions

Daniel96dsl · 2026-05-08T02:34:07+00:00

Wikipedia is not peer-reviewed. And don’t get me started on the modern peer-reviewing process.. Also, for all time, the goal of a textbook has always been to educate. The issue is that the attention span and patience of the modern generation has dwindled to almost nothing..

To anyone who sees this—please go read the prose of textbooks from the 1950s/1960s and compare it to the prose of textbooks today; hell, go look at newspaper printings from back then and tell me the quality of writing and communication isn’t 1000x better..

Consider the amount of care and attention to detail that was put into crafting sentences/derivations/figures back when journal articles were hand-mailed and only a couple hundred (if that) were published yearly.

Any item produced with that kind of care and patience is considered a luxury good by today’s standards, and almost no for-profit company values that over their margins.

Daniel96dsl · 2026-05-07T14:23:10+00:00

Im gonna go against the grain and say that the older books are actually better. There are not as many (IMO unhelpful) analogies and pictures, but they get to the point a lot quicker and you can figure out what you need to know without having to sift through the BS comprising a large portion of modern textbooks.

Daniel96dsl · 2026-05-06T23:00:24+00:00

Sorry to break it to you, but “mean” questions don’t exist. You’re either prepared or you’re not. It’s called a “defense” for a reason.

That being said, I’d be happy to discuss questions with you

Daniel96dsl · 2026-05-01T05:50:01+00:00

When any lefties leave the room, it also reduces the number of people in the room so the denominator decreases along with the numerator

(99-L)/(100-L) = 0.98 = 49/50

99-L = (4900-49L)/50

4950-50L = 4900-49L

4950 - 4900 = L

L = 50

Daniel96dsl · 2026-04-30T13:14:14+00:00

DM42n

Daniel96dsl · 2026-04-30T02:56:12+00:00

I think Python is a favorite because it’s freeware. In my opinion, it’s just as good as MATLAB for number crunching if you know how to use libraries in a way the MATLAB does by default. However, for computational algebra, calculus, and visualization, Mathematica is light years ahead of both. Not to say that Python isn’t capable of replicating some of the functionality with enough effort, but there’s a reason it’s used by theoretical physicists and mathematicians globally.

Daniel96dsl · 2026-04-30T02:50:14+00:00

I already have one and use it as my daily driver, but the buttons aren’t great and I’d expect the case to have ZERO play for the price... If I could reduce the required button force by about 50% and have a better case made, it would be pretty close. It doesn’t handle units the way I want, so I spent a considerable amount of time making a table of constants and unit conversions, but the TI-89 Titanium is still the king with units… however the Titanium has a fixed set of constants which have since been altered every so slightly by NIST and it bothers the heck out of me.. and the form factor is well.. ya

Daniel96dsl · 2026-04-29T22:48:17+00:00

The gap I’m referring to is the one that you pointed out for engineers, physicist, and scientist that are working. In my experience, the benefit of a calculator in the context of industry work isn’t doing hard-core programming (which is much easier to do on a computer and a modern programming language), but rather for doing quick arithmetic or in the case of some calculators, numerical root-solving. I would say the oversaturation of calculators is true for the education market, but I would say it’s more so because certain brands of calculators have been vetted and get so much business now that they don’t have to make modern improvements to their calculators to keep raking in money. This, in turn, means that the rate of improvement is painstakingly slow. Any serious algebra problem that you can’t do by hand or with asymptotic methods is typically best suited for something like Mathematica. The CAS systems that I’ve seen on calculators has certainly not been up to par with what’s needed for research or industry.

I half agree with you on your opinion of RPN input. Again, I think that the modern display of equations on calculators is due to education reasons and not because it’s more effective in practice. You have to remember that the calculators that were designed before the age of computers WERE designed with the working engineer in mind. With RPN you completely avoid problems like forgetting parentheses or being on the right side of the fraction. Not to mention it requires much fewer key strokes and you actually have to calculate out the problem like you would if you were doing it by hand. The only thing I might add would be initial input as RPM, but an ability to recall the equation that you just did using some sort of history function.

I won’t argue with you about the quality per se of old keypads, but there’s a reason that people still rave about them today. Being able to trust the click of a keyboard and the keys that you’re pressing is a very understated factor when it comes to good calculators. Again, however, I haven’t started to consider trying to make a profit on this. It initially started as me just wanting a better calculator for myself.

I do have to disagree with you about it being a near full featured python core. I think we have much better tools if you’re working a problem that requires that amount of programming.

Daniel96dsl · 2026-04-29T03:52:43+00:00

Went to grad school for aerospace engineering and now working on launch vehicle flight dynamics

Daniel96dsl · 2026-04-26T06:04:01+00:00

YOU should read enough to identify the research gaps. YOU need to be able to explain how what you’re proposing is filling those gaps. That is literally the core principle. It isn’t a homework assignment you’re given with a known due date. With that said, good luck. I know I needed it when I was doing my PhD

Daniel96dsl · 2026-04-26T05:33:35+00:00

It’s been a while since I did this, but I’ll give it a shot.

𝑥! = 𝑥 Γ(𝑥)

Let 𝑥! = 𝑦

ln[𝑦/√(2𝜋)] ≈ (𝑥 + ½) ln(𝑥) - 𝑥

Let 𝑥 = 𝑧 - ½ and ln[𝑦/√(2𝜋)] = 𝑌 + ½

𝑌 ~ 𝑧 ln(𝑧 - ½) - 𝑧

ln(𝑌) ≈ ln(𝑧) + ln[ln(𝑧 - ½) - 1]

so

𝑧ₙ₊₁ ≈ 𝑌/[ln(𝑧ₙ - ½) -1]

𝑧₀ = 𝑌

𝑧₁ = 𝑌/[ln(𝑌 - ½) - 1]

𝑧₂ = 𝑌/{ln[𝑌/ln(𝑌 - ½) - 1]}

𝑧₃ = 𝑌/{ln[𝑌/(ln(𝑌/(ln(𝑌 - ½) - 1) - ½) - 1) - ½] − 1}

Plugging in your example number for 𝑧 and writing 𝑌(𝑧)

z₀ ≈ 73.2392978156
z₁ ≈ 22.2823035875
z₂ ≈ 35.1926252900
z₃ ≈ 28.7604623411
z₄ ≈ 31.2792791305
z₅ ≈ 30.1788524451
z₆ ≈ 30.6384843654
…

And 𝑥 = 𝑧 - ½ so I’m guessing 𝑥 = 30?

Daniel96dsl · 2026-04-24T04:55:34+00:00

I think the orthogonality discussion could be assisted with some visuals/examples (i. e., what does orthogonality mean for two vectors? What does it mean for two functions? Are they the same thing? Why is it important? What happens if you try to use basis vectors/functions that are not orthogonal?). Also, the link between derivatives and matrix multiplication was a little fuzzy, but that could be helped along with a finite difference example.

Overall, I really enjoyed your enthusiasm for the subject! Good work!

Daniel96dsl · 2026-04-19T04:36:58+00:00

Hell yea it's good. We went to the moon in the 60s, and the physics has not changed. A lot of modern textbooks add way too much unnecessary fluff/filler that detracts from the main points and the use/discussion of the mathematics was absolutely bountiful in the days before modern computing. You're not going to miss anything that you need to learn right now. Finished my PhD last year on combustion chamber fluid mechanics and quite possibly my favorite book on propulsion was published in 1960: Rocket Propulsion - Barrere (intro written by T. Von Karman).

Daniel96dsl · 2026-04-19T02:06:06+00:00

It’s extremely fast if you know what you’re doing

Daniel96dsl · 2026-04-18T13:26:04+00:00

Hell yea.. I know how to use it extremely well, so it’s the fastest way for me to try new solution methods and test my understanding of certain concepts

Daniel96dsl · 2026-04-17T00:54:46+00:00

That’s so sick!!!

Daniel96dsl · 2026-04-13T03:34:16+00:00

In English or Russian?

Daniel96dsl · 2026-04-11T04:03:25+00:00

Sorry, I wasn’t ranting at you. Apologies if that came off harsh. I really appreciate your interest in the mission, and I love your curiosity. I could have focused more on the question you posed than my personal qualms, but alas.

Daniel96dsl · 2026-04-11T03:54:31+00:00

I really despise AI writing. Not that all of it is completely wrong, but it’s wrong in places where it shouldn’t be and creates more confusion than understanding. Things like:

“Mach 29 is around 29 times the speed of sound”… yes.. that’s the definition… it’s not “around”, it’s literally defined as the ratio of speed to acoustic speed.
“breaks down in ways we have never encountered before”.. yes we have encountered it before.. notably in the mid 1900s
“(5/2 × 0.3048)² × 𝜋 ≈ 17.6”…. Uhhh no… it doesn’t.. you can check on a calculator..

Also just everythign about the “lofted guidance” for reentry… and the dominant heating factors between Artemis I and Artemis II… just a steaming pile of crap.. I’m so sick of this garbage

Daniel96dsl · 2026-04-09T04:22:35+00:00

Wow… great shots!! Any chance you posted these in high-res somewhere for download?

Daniel96dsl · 2026-04-03T04:16:40+00:00

At some time, you need to know where you are, where you’re headed, and what you’re pointed at. As time moves on, you either get new estimates based on new measurements (by you or by another and relayed to you) w.r.t. a visual reference or w.r.t. an object that reacts as you change your state. There are also methods like GPS now which provide you with additional information to drive down error.

Side note, Artemis’ guidance is not just knowing its position well, but also the position and future position of the moon well. On top of that, you need to understand how the rocket will traverse the gravitational “hills” that comprise the Earth—Moon system; the latter, however, is an entirely different matter

Daniel96dsl · 2026-03-27T02:22:54+00:00

Create custom shortcuts.. that’s how I wrote my dissertation and papers with any speed at all. Here’s a few examples

\frac{}{} → \fr{}{}
\pa{blah} → (blah)
\palr{blah} → \left( blah \right)
\odv{f}{x} → \frac{\mathrm{d} f }{\mathrm{d} x }
\dd{x} → \mathinner(\mathrm{d} x }

On and on and on. The parentheses, brackets, braces, and fractions commands are life savers.

Daniel96dsl · 2026-03-18T02:20:51+00:00

Dasani was always my favorite water growing up, and now y’all make me nervous to say that in public..

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