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Thread: My TI-84 Plus Calculator

  1. #1
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    My TI-84 Plus Calculator

    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.

  2. #2
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    Quote Originally Posted by lowell holmes View Post
    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.
    Sharp solves all manner of problems.

  3. #3
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    That's the correct answer, for 30 radians. Change your angular units from radians to degrees.
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

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    Quote Originally Posted by David L Morse View Post
    That's the correct answer, for 30 radians. Change your angular units from radians to degrees.
    Or learn how to think in radians.

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    Quote Originally Posted by Mike Kreinhop View Post
    Or learn how to think in radians.
    My solution is to keep a copy of this in the shop:

    Trig Tables.png

    Then put pencil to paper.

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

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  6. #6
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    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.
    Last edited by lowell holmes; 02-23-2020 at 6:28 PM.

  7. #7
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    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.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  8. #8
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    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)

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    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.

  10. #10
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    Quote Originally Posted by Rod Sheridan View Post
    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!!
    Jason

    "Don't get stuck on stupid." --Lt. Gen. Russel Honore


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    Quote Originally Posted by Rod Sheridan View Post
    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

  12. #12
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    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.

  13. #13
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    I have a slide rule and know how to use it.

  14. #14
    Quote Originally Posted by Rob Luter View Post
    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.

  15. #15
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    My 15C is in front of me now. I use it all the time. Another vote for RPN
    Beranek's Law:

    It has been remarked that if one selects his own components, builds his own enclosure, and is convinced he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion.
    L.L. Beranek, Acoustics (McGraw-Hill, New York, 1954), p.208.

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