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Homework Help: Make d/t and v/a graphs

  1. Mar 1, 2005 #1


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    Hi guys, im doing a lab in physics, which requires me to make d/t and v/a graphs. Our teacher wants the graphs to be nice and smooth with tangent lines and everything, thing is, i dont know what prgram to use. He said no excel because they dont give u smooth lines. Any ideas?... Any help would be appreciated. Thnx.

    - Tu
  2. jcsd
  3. Mar 1, 2005 #2
    Maple, Mathematica, and Matlab will all do this. You can also tinker with GnuPlot and get some very nice graphs. Excel was never made for mathematical applications, and so has some major short comings with making nice graphs with tangent lines and such.

    The downside is that most of the best programs are not free. GnuPlot is free, and good, but it's tricky to learn how to use properly. It can, however, do best fit lines, calculate slopes between given points, and (I think) create tangent lines.
  4. Mar 1, 2005 #3


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    You may want to do Regression (also called "Curve Fitting") on your data. These mathematical routines determine and graph a smooth "Best-Fit Curve" thru your data points. The type of curve is selectable, usually ranging from Linear to Polynomials of various degrees. For your lab, it appears you might want Linear Regression ("Linear Curve Fitting") for the "v/a" data, and Polynomial Degree 2 ("Quadratic") Regression for the "d/t" data.

    If your lab cannot provide Regression programs, try the following site, which offers no-frills Regression capabilities thru your browser. Scroll all the way down the page for the program. Enter your data in the top panel, select Regression type ("Polynomial") and Degree ("1" for Linear, and "2" for Quadratic), and the program will graph the Best-Fit smooth curve thru your data. Formulas for the smooth curve are provided in the bottom panel, and you can determine tangent lines by differentiating these formulas. (For report purposes, you'll may want to "Screen Capture" the results.) Good Luck!!

    Last edited: Mar 1, 2005
  5. Mar 2, 2005 #4
    Hey neat link xanthym. :smile:
  6. Mar 2, 2005 #5
    If you have access to it, there's a program called Graphical Analysis that was specifically designed for graphing physics labs on the computer. It calculates the Best Fit curve for you using either direct or indirect equations and then tells you what the lowest MSE is so you can pick the best fits for that particular set of data
  7. Mar 2, 2005 #6


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    He would also be wrong if that is what he said. There are certain graph types you would have to choose, but it is definitely do-able in Excel. You can do a fair amount of regression analysis with Excel by using their included regression tool. If you do it by hand you can do whatever you like.
  8. Mar 2, 2005 #7


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    thnx alot guys... i'll deffinitely tryout some of these programs.

    - Tu
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