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Advice how to up my scientific computing with I-pad and otherwise.

  1. Oct 6, 2013 #1

    epenguin

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    When there are answers this might be suitable for Math Learning Materials

    My untrusty HP48GX graphic scientific calculator conked out two or three years ago and since then for my limited needs (e.g graphs on this forum) in that time I used odd little programmes I found around for graphics and a few computings of 1st order d.e.'s. and other odd graphs.

    Now I need to get back into some scientific computing.

    There is quite a difference between a handheld device like my old one and sitting at a computer. Like you just do more with a handheld than with a machine you, as it were, make an appointment with. But the handheld math calculator seems now to me a dated concept and surely I can do all I did before better now on the iPad with its more serious graphics etc. with apps? I wonder what you can recommend for my requirements and criteria.

    My needs

    Now:

    right now I want to calculate out curve families for algebraic etc. functions that may involve equations solving

    Including functions given by programmes

    And right now just 1st-order nonlinear ode's aka phase plane plots.

    More demanding I want symbolic manipulation. I find chains of algebraic substitutions, expansions, cancellations etc. not only boring but I am very error-prone. The old HP was quite limited, and some calculations could take even hours with cycles of expanding and collecting for instance without knowing too much what it was doing, yet when it did in its stupid fashion work, end results were error-free and so saved me time. So I need something like that, only better, I also want it to handle determinants and matrices etc., but symbolically not just numerically.

    Later:

    Higher order d.e.s, and PDE's in 1, 2, 3 D so maybe pretty usual stuff for many of you.

    Possibly more special, I shall probably be wanting to do algebraic calculations with hundreds of terms, not really doable at all by hand.

    As far as possible I want one app, or not too many different things. Maybe expandable. I find you can spend a lot of time finding your way around each new app if you don't use the same one, plus could paying for things not used much.

    Perhaps the only thing for later on is Mathematica? I did try it about ten years ago and I think I can still find it on an old disk. I didn't do much: I have a couple of manuals, but at the time, not being a very computer person, they appeared to me a lot of words from which I was unable to extract any operational meaning (what to do) or any at all.

    I see it has come down in price since then and there is a home version. At £200 I would wait for a bit. I couldn't make out if you can use it on or with the iPad. OTOH free apps don't usually seem to amount to much - I've seen some I wouldn't put in the hands of an early secondary school student, they are so absurdly limited.

    I should say I am now outside of any academic institution and this is for work I'll do at home.

    What strategy and products would you advise for someone like me to get an act together? (Never in professional math as such but got into mathy stuff via biology).
     
    Last edited: Oct 6, 2013
  2. jcsd
  3. Oct 6, 2013 #2

    Office_Shredder

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    wolframalpha.com will do almost anything you want it to. I don't know if you have to buy the app for an ipad or if you can visit the website directly, but I would be surprised if you could find anything more effective for the price either way.
     
  4. Oct 7, 2013 #3
    Office_Shredder beat me to it. www.wolframalpha.com is the best calculator there is. As stated above me it can do almost anything you want it to.

    Wolfram Alpha actually has an app for the Android, which means that they should have its counterpart on the Ipad. Unfortunately, you need to be connected to the internet to use the application. However, Wolfram Alpha's awesome contributions are laudable and they deserve some compensation, so I'd advise you to support them and purchase the app.
     
    Last edited: Oct 7, 2013
  5. Dec 21, 2013 #4

    epenguin

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    Thank you for those replies. I did not come back before because I wanted to try it out more. The fact is I had already downloaded and tried to use WolframAlpha before starting this thread and given it up as too difficult.

    I found it hard to find any instructions in the app. I did find some at one point but now can't again. I eventually found ones that worked for some things at Wolfram Mathematica 9 Documentation Center - I think this is the same grammar.

    A few things did work. I was able to work out an expansion of a polynomial which gives 80 terms, impossible by hand (it must have condensed and simplified too). Have not succeeded well d.e.'s yet, not so simple, but promising.

    But just now I have been stuck unable to solve a simple cubic (that came up from a problem on this forum) numerically.

    My input:

    FindRoot [(0.1434-3*0.0797)+X*(0.1434-2*0.0797)/(7.1*10^-13)+X^2*(0.1434- 0.0797)/(7.1*10^-13*6.7.1*10^-13*10^-8)+X^3*0.1434/(7.1*10^-13*6.7.1*10^-13*10^-8*7.11*10^-3), {X,0}]

    gets only response:

    alpha does not know how to interpret your input

    Did you mean
    0.1434- 0.0797 ? '

    I don't know how to tell it the answer, but I wonder what is ambiguous about 3* ? I tried various variations of bracketing and spacing, and also the ==0 option.

    So yes it looks in some ways like the way to go, and I might maybe later expand into Mathematica if necessary and I get really serious. But on the other hand I will never get to that point at this rate if I stick for two days trying to work out how to make it multiply by 3.

    Have you any suggestions for this particular puzzle at least please?

    (I remember I did try to work with Mathematica some years ago and have a big manual. But just in the first chapter it was to me like a lot of words to which I could not attach any operational meaning. Maybe I am a bit more computer-minded now.)
     
  6. Dec 21, 2013 #5

    Mark44

    Staff: Mentor

    I don't know how to interpret your input, either.
    For starters, you need to fix what seem to me to be obvious typos (in red). If WA still can't decipher this, I would put the exponents in parentheses. WA probably can comprehend 10^-13, but the LaTeX interpreter doesn't render expressions like this correctly.
     
  7. Dec 22, 2013 #6

    epenguin

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    Thanks, that did it and I am now getting the sort of solutions I expect.

    In my defence the thing the program couldn't interpret was at the other end of the formula, the start, or at least it looked to me like that because there are several quite similar expressions, so maybe that confused me I was not looking for problems in the right place further along. Not sure how LaTex comes into this. But I have been storing the versions of the expression on my notebook - the app has a window shorter than the expression and as you try to edit it is very easy to lose the whole thing.

    But anyway this is looking much more promising now! I hope I can ask if I run into further problems. :smile:
     
  8. Dec 22, 2013 #7

    Mark44

    Staff: Mentor

    My point about LaTeX was that you have to pay attention to proper syntax usage in whatever language you are using. Part of WolframAlpha is an engine that parses the expressions you type into the input window. When you type something in that it can't handle, such as 6.7.1, it chokes. I wasn't sure if it could handle 10^-13 with no parentheses around the exponent (i.e., 10^(-13)).
     
  9. Dec 22, 2013 #8

    Borek

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    On the one hand - it is good to have WA around.

    On the other hand - I wasn't raised this way, I hate the idea of requiring a connection to do math. Internet? Connection? Wireless? That's ridiculous.

    I am starting to wonder if the dinosaurs didn't die out of disgust seeing how the world was changing. Mammals? Active in the night? Sucking milk :yuck: That's ridiculous.
     
  10. Dec 22, 2013 #9

    Mark44

    Staff: Mentor

    I agree. We didn't even have calculators in my college math classes, let alone something as sophisticated at WA. Being 100% dependent on an electronic device seems overly optimistic to me.
     
  11. Dec 23, 2013 #10
    I volunteer-TA'ed with the SPS at my college and had a student that was getting A's on all homework, but failing tests. He was complaining one day about the class saying the homework didn't prepare him for the tests. He said the homework was easy because he just had to put it into WA. I said that the point of the homework was to think about the problems. He didn't have time for that... unfortunately, he had the entire next semester when he needed to retake the class.

    That being said, when used right, Both Alpha and Mathematica are excellent.

    There is a TI-84 emulator called wabbit that I've heard works well. I don't know if you have to purchase anything for it though.
     
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