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Jernej last won the day on December 2 2009

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  1. Anybody got the full book? Would be much appreciated ...
  2. Jernej

    Body Mass Index

    It's polynomial of 3rd degree or higher. Should you choose this option, I've posted the instructions on how to obtain polynomial of any degree (up to maximum number of points in your set of data, to be precise) here. You will find data for median BMI of females here. Another option is to mess around with the sine or cosine function. I can also assist you with this one if you like, but I'd go for polynomials if I were you.
  3. Jernej

    - Fishing Rods Type 2

    How to model your qaudratic and equation using GDC or any other math software capable of matrix operations: 1.) Consider general form of cubic and quadratic equations (where a,b,c,d are coefficients and where a is never zero): y=ax2 +bx+c (quadratic) y=ax3 +bx2 +cx+d (cubic) 2.) Insert points from the graph (x,y coordinates) into general from of the equation to get a system of equations (example): 4a+2b+c=7 (point 2,7 in quadratic equation) 9a+3b+c=8 (point 3,8 in quadratic equation) 16a+4b+c=5 (point 4,5 in quadratic equation) 3.) For three points, quadratic equation equation is a polynomial fit, for four or more, it is a polynomial regression (hence, at least three points are required). For four points, cubic eqaution is a polynomial fit, for five or more, it is a polynomial regression (hence, at least four points are required). Remember, that polynomial fit means, that a polynomial passes through these points and that polynomial regression means that polynomial fits to the general shape that points form, but never actaully passes through any of the points. In any case, finding an equation of the original curve is pointless, because the most accurate regressions are the ones from 4th degree polynomials and up and you have to deal with 2nd and 3rd degree polynomials. Be more specific about the task you're working on. 4.) Having made system of equations, rewrite them in matrix: Apply rref command in your TI-84 GDC (2nd -> Matrix -> Math -> rref). I used Maple 12 for clarity. 5.) All you are now left with is the read the coefficients of your equation: a=-2, b=11, c=-7 and write the regression equation: y=-2x2 +11x-7 6.) Finally, to visually check the correctness of your results, you can plot regression equation and points you used all of them. I used my three points and obtained equation (note that this is a polynomial fit): (I used Autograph to create this graph) This should be it. Hope it helped.
  4. Jernej

    Matrix Binomials

    What exactly are you required to do? You can express 3n+1 as (n+1)log(3) or 3n+3.
  5. Jernej

    IA topic

    Suggestions: 1.) Examining tidal differences with sinusoidal model. 2.) Modelling population growth using polynomial model. 3.) Exploring surface area of liquid droplet that had fallen on a medium in dependece of time. ... Ran out of ideas really ...
  6. Jernej

    Body Mass Index

  7. Jernej


    I am not sure what exactly you are trying to calculate. I found online [b][url="http://education.ti.com/guidebooks/graphing/84p/TI84PlusGuidebook_Part2_EN.pdf"]manual for TI-84 (click)[/url][/b], where you should find everything you want to know about this (great) GDC. Parts of the manual, which I think should answer your question are: [img]http://fiona.t-2.net/kakarun/pg307_man.png[/img] (Page 310) [img]http://fiona.t-2.net/kakarun/pg590_man.png[/img] (Page 593) I hope this helps you.
  8. Jernej

    Name Your IB School

    Gimnazija Bežigrad, Ljubljana, Slovenia (IB school code: 000562) Photo of school: On Google maps (click) I am May 2009 IB Diploma Candidate.
  9. Jernej

    Interview: Who are you?

    1. What is your real name? Jernej. 2. Where are you from? Ljubljana, capitol of Slovenia, Europe (next to Italy and Austria; NOT to be confused with Slovakia). 3. How did you find out about IB Survival? 4. What made you register on IB Survival? Overall neatness of the forum and usefulness of the information. 5. When did you (approximately) register here? Thursday, 8th May 2008. 6. What is your favourite IB subject? Biology. 7. When are you graduating? Friday, 22nd May 2009. 8. What are your plans for university? Study Medicine at University of Ljubljana and move to UK, Germany or Denmark ASAP. 9. What are your free-time hobbies? Computing, cycling, swimming, playing drums, sleeping, playing billiards, reading various scientific magazines and journals, web surfing, blogging, googling and, last but not least, helping out people with what I can, where I can, whenever I can. 10. If you could change one thing on IB Survival, what would it be? I find IB Survival rather perfect at the moment. I trully hope that it will remain a great site, ran by dedicated and diligent people who will always be there to help out and expand community as time goes by.
  10. Jernej

    How is a Lab Report supposed to be?

    I concur wiht IBDoc. However, to really make sure that you're making your report by the book, you should take a look at the official IB Criteria which are attached here at your convenience (extracted from the official IB Biology Syllabus for 2009 Examinations, which can also be found here: http://www.ibsurvival.com/forum/index.php?...pic=20#Biology) Biology_IA_Criteria.pdf Cheers, Jernej
  11. Jernej

    Marking bounderies

    75-85 for 6. Source: http://www.thestudentroom.co.uk/wiki/IB_Gr...oundaries#Maths
  12. Jernej

    Body Mass Index

    I found data for Guatemalan kids: http://www.unu.edu/unupress/food2/uid02e/uid02e0e.htm Better than nothing - we also had to hand in completed portofolios two weeks ago ...
  13. In addition to what was mentioned, I would also like to add the following: DeadLine: http://deadline.3x.ro/ - equations solver and plotter; very useful for math homework (functions, derivatitves), but unfortunately only works under Win32. Maple 12: http://www.maplesoft.com/products/Maple/index.aspx , http://en.wikipedia.org/wiki/Maple_computer_algebra_system - all-you-need software for IB Math with very intuitive interface. Only con: shareware (pro: you can find serial in no time ... ) GeoGebra: http://www.geogebra.org/cms/ - excellent free and multi-platform software that joins geometry, algebra and calculus. Nuff said. Autograph: http://www.autograph-maths.com/ - very good shareware math software especially good for function graphing (draws beautiful graphs by default). AnalyticMath: http://www.analyticmath.com/ - FREE, cross-platform (Windows, Linux, etc.) mathematics / plotting program with a powerful editor and integrated 'auto-calc' features that will help you develop and visually analyse mathematical expressions quickly and easily. The program is intuitive, simple to use, and suitable for everyone from students to theoretical physicists and, of course, IB students as well. Maxima, a Computer Algebra System: http://maxima.sourceforge.net/ - Maxima is a system for the manipulation of symbolic and numerical expressions, including differentiation, integration, Taylor series, Laplace transforms, ordinary differential equations, systems of linear equations, polynomials, and sets, lists, vectors, matrices, and tensors. Maxima yields high precision numeric results by using exact fractions, arbitrary precision integers, and variable precision floating point numbers. Maxima can plot functions and data in two and three dimensions. It is available for Windows, Linux, and MacOS X and is also one of the must-haves for either IA or Math homework and is also of great use at Physics and Chemistry as well. If you prefer simplicity over functionality, here are some other popular alternatives to Windows Calculator and unit conversion: Calculator (Mozilla Firefox Extension): https://addons.mozilla.org/en-US/firefox/addon/1194 - just what is says. Microsoft Calculator Plus: http://www.microsoft.com/downloads/details...;displaylang=en - a bit better than Windows Calculator since it has conversion tab. Big wow for nothing and you have to validate your Windows copy, download bulky Windows Installer and all you get out of it is a little .exe with a slightly more functionality than Windows Calculator. For those of you, who would just like to double-click and try, I uploaded the .exe file in the attachement below. CalcPlus.zip This is how I struggle through IB course and it would be much harder for me if it weren't for software you've already mentioned and the one I listed here.

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