Thread: Matlab help

  1. #1
    Registered User
    Join Date
    Dec 2006
    I just started learning Matlab again after not having used it in months, and got some odd results -

    Trying to plot tan(x), from -pi/2 to pi/2 -
    X = (-pi/2):pi/100:(pi/2);
    for i = 1:length(X)
         Y(i) = tan(X(i));
    I ended up getting something that has a negative spike at 0 and positive spike at 100. Certainly doesn't look like tan(x) to me.
    I'm sure it's something simple, but it's been an hour already...

    Ah! Ok. It seems like the big dynamic range threw Matlab off somehow. Adding clamping works.
    Last edited by cyberfish; 03-07-2011 at 03:55 AM.

  2. #2
    Make Fortran great again Epy's Avatar
    Join Date
    Sep 2009
    California, USA
    You don't need that for loop, tan() and many other functions accept/output arrays:

    Y = tan(X);

    Also, you need to plot against an independent variable:


    It looks sharp because pi/100 isn't a small enough step size, try .01 lower
    Last edited by Epy; 03-07-2011 at 06:56 AM.

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