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 Author Comment/Response Tom 09/24/10 4:12pm Hi, What's the best way to graph a pendulum's motion (without using the approximation Sin[theta] ~= theta for small theta)? The DE is given by http://upload.wikimedia.org/math/8/c/a/8cac81164940cc01c636c5c4d2592d48.png . I've tried using g = 9.80; l = 2.0; v0 = 5; f = \[Theta] /. First@Flatten@ NDSolve[\[Theta]''[t] + g/l Sin[\[Theta][t]] == 0 && \[Theta][0] == 0 && \[Theta]'[0] == v0, \[Theta], {t, 0, 20}] Plot[f[t], {t, 0, 20}] But the plot increases instead of oscillating. What should I do to get a better graph? Thanks, Tom URL: ,

 Subject (listing for 'NDSolve a pendulum's DE') Author Date Posted NDSolve a pendulum's DE Tom 09/24/10 4:12pm Re: NDSolve a pendulum's DE yehuda ben-s... 09/26/10 03:46am Re: Re: NDSolve a pendulum's DE Tom 09/26/10 8:29pm
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