My TI-84 Plus Calculator

[lowell holmes]

Is giving erroneous answers. It shows the sin of 30 degrees is .9880516241
It is an old calculator.Should I trash it? The answer should be .5 ???

Maybe it is time to trash it.

[Rob Luter]

Is giving erroneous answers. It shows the sin of 30 degrees is .9880516241
It is an old calculator.Should I trash it? The answer should be .5 ???

Maybe it is time to trash it.

Throw it away. Get a Hewlett Packard. HP knows math. RPN rules.

[David L Morse]

That's the correct answer, for 30 radians. Change your angular units from radians to degrees.

[Mike Kreinhop]

That's the correct answer, for 30 radians. Change your angular units from radians to degrees.

Or learn how to think in radians. :)

[Jim Koepke]

Or learn how to think in radians. :)

My solution is to keep a copy of this in the shop:

426588

Then put pencil to paper.

For me a calculator may be handy but it seems to make the brain lazy.

jtk

[lowell holmes]

You nailed it. I changed the batteries in it and some how changed it to radians.

My daughter who is an engineer told me. And Jim I am printing a table as well.

[Jim Koepke]

And Jim I am printing a table as well.

Maybe if a bit more of my youthful time was spent on learning a slide rule my pencil could be spared. :rolleyes:

jtk

[roger wiegand]

I have found a couple good calculator apps that run on my phone. I particularly like PCalc Lite because it is free, simple, does RPN, and the icon is a button with "42" on it. (that being The Answer to life, the universe, and everything)

[Rod Sheridan]

My trusty HP11C is still running fine.

I found an app for the Ipad that is an emulator of an HP45, now I have a calculator on my Ipad that I can actually use. Of course my kids think my love of RPN and HP calculators is just lame.......Rod.

[Jason Roehl]

My trusty HP11C is still running fine.

I found an app for the Ipad that is an emulator of an HP45, now I have a calculator on my Ipad that I can actually use. Of course my kids think my love of RPN and HP calculators is just lame.......Rod.

I have one that is a 42S emulator--the same calculator I got in high school, and still have. Sadly, the real one gets used so little that I have to put new batteries in it each time (it usually only got used at tax time). But with the phone app, I think it's probably permanently retired.

Long live RPN!!

[Tom Stenzel]

My trusty HP11C is still running fine.

I found an app for the Ipad that is an emulator of an HP45, now I have a calculator on my Ipad that I can actually use. Of course my kids think my love of RPN and HP calculators is just lame.......Rod.

My HP 11C still works fine too. The manual would in good shape too if a fountain pen hadn't made a big blot on the cover, er, um, a while (meaning about 30 years) ago.

On my phone I use:

https://thomasokken.com/free42/

Available for iOS, MacOs, Windows, Linux, Android. Does a lot more than I will ever need in a calculator. Or know how to use.

My kids think I'm lame even if I didn't have a RPN calculator.

-Tom

[Don Coffman]

My 42S display is about dead. I found a emulator free42 binary I use on my android as well under Win10 on my laptop ..... RPN forever.

[lowell holmes]

I have a slide rule and know how to use it.:)

[Doug Dawson]

Throw it away. Get a Hewlett Packard. HP knows math. RPN rules.

RPN was the future 50 years ago, and it still is. That said, I love it. Think with the stack you will. It just makes sense. I don't buy into the phone simulations, there's nothing like the instant key gratification of the original metal. You can still get it on eBay, I'm told.

[David L Morse]

My 15C is in front of me now. I use it all the time. Another vote for RPN

[Rob Luter]

Glad to see some fellow RPN guys here. I've been an HP guy since 1983 with my HP10C and wouldn't have it any other way. It makes for a very narrow demographic that wants to borrow your calculator at work. It's fun to watch first timers look for the equals button. I finally retired the 10C a couple years ago and got a 35s. Still getting used to the different key locations.

[Jason Roehl]

Yep, the Free42 emulator is what I use. I liked using my 42S when I got it in 1991-ish, but there's no way I'm carrying that around with me all the time--it's the same size as my iPhone...which runs the 42S emulator just fine.

Anyone know what the layout is when you rotate your phone with the Free42 app?

[Ted Calver]

Love RPN...and my old HP-11C!

[Steve Demuth]

Glad to see some fellow RPN guys here. I've been an HP guy since 1983 with my HP10C and wouldn't have it any other way. It makes for a very narrow demographic that wants to borrow your calculator at work. It's fun to watch first timers look for the equals button. I finally retired the 10C a couple years ago and got a 35s. Still getting used to the different key locations.

I still use my 1973 vintage HP45 on occasion for nostalgia. I had two at one time, but a bunch of LED segments crapped out on one, making it a bit of challenge to read accurately. Mostly I use an HP45 emulator on my cell phone or a cheap Fire tablet that I bought to kick around in the shop. I also have a 50th anniversary edition HP32S. Unfortunately, they have a common failure mode in which a contact separates under the shell, making certain keys inoperable unless you hold it just right. But I still use it at my work desk anyway.

I've never understood how anyone who could do math with more than 3 operations in an equation ever tolerated algebraic notation calculators once they were shown RPN.

[Jim Koepke]

I've never understood how anyone who could do math with more than 3 operations in an equation every tolerated algebraic notation calculators once they were shown RPN.

Different minds work in different ways. For me RPN would often end up with an error due to forgetting to hit the enter key or hitting an operand key before inputting the next part of the equation.

It has been so long since using an RPN calculator would likely give me problems. Back when my life included more math the work was often done in my head. Back in the day it was fairly easy for me to multiply three digit numbers with no problems. On a good day even four digit multiplications could be done without breaking a sweat.

jtk

[David L Morse]

Different minds work in different ways. For me RPN would often end up with an error due to forgetting to hit the enter key or hitting an operand key before inputting the next part of the equation.


Interesting contrast. My most common error is leaving out the opening parenthesis when entering a formula in a spreadsheet. I need to be careful when it's not RPN..

[Rod Sheridan]

RPN was the future 50 years ago, and it still is. That said, I love it. Think with the stack you will. It just makes sense. I don't buy into the phone simulations, there's nothing like the instant key gratification of the original metal. You can still get it on eBay, I'm told.

I have both an HP45 on my Ipad, and an HP11C that's still in daily use.

The HP is a great sit on the desk calculator as no one at work ever borrows it, I'm the only one old enough to use RPN:eek:

[jared herbert]

I have several slide rules and use them occasionally. When I was in college I had a job correcting papers for a freshman engineering slide rule class talk about boring. I try to do most of my calculations in my head-I seem to have knack for that. 4 function calculator and a paper tablet helps out too.

[Steve Demuth]

I have several slide rules and use them occasionally. When I was in college I had a job correcting papers for a freshman engineering slide rule class talk about boring. I try to do most of my calculations in my head-I seem to have knack for that. 4 function calculator and a paper tablet helps out too.

I do almost anything not involving division to a high precision in my head or on paper. Division past 2 digit precision, or involving more than 3 digit operands is beyond me anymore, and I reach for a calculator. But what I really use the calculator most for in the shop, is trigonometry, and of course the multiplication and division that always follow looking up a sine or cosine or tangent.

[Lee DeRaud]

Another vote for RPNStill waiting for a plausible explanation for how RPN would have helped with OP's original problem...

[Doug Dawson]

Still waiting for a plausible explanation for how RPN would have helped with OP's original problem...

The original problem was solved. Going off on tangents is more entertaining.

[Rob Luter]

The original problem was solved. Going off on tangents is more entertaining.

^This^

Now I’m wondering what water stone grit I need to increase my calculator’s accuracy to several more decimal places. Probably something pretty fine....

[Günter VögelBerg]

Best day of college was taking final math class and listing that thing on ebay.