Thread: Mathematica 7.0, plotting x*sin(x), weird looking graph

The command I'm using is

Code:

Plot[{x*Sin[x]}, {x, -80 Pi, 100 Pi}]

and I get this weird result. Look at x= approx -80 and 130.


Some other similar intervals involving pi also give weird results looking almost like that. There are at least four options:

1. I'm too dumb to realize it's supposed to look like that
2. My computer is broken
3. Mathematica is broken
4. It's not a bug, it's a feature.

So my question is, does this happen to anyone else using Mathematica (v7.0.1.0)?

Originally Posted by mathpath

The command I'm using is

Code:

Plot[{x*Sin[x]}, {x, -80 Pi, 100 Pi}]

and I get this weird result. Look at x= approx -80 and 130.


Some other similar intervals involving pi also give weird results looking almost like that. There are at least four options:

1. I'm too dumb to realize it's supposed to look like that
2. My computer is broken
3. Mathematica is broken
4. It's not a bug, it's a feature.

So my question is, does this happen to anyone else using Mathematica (v7.0.1.0)?

need to specify more sampling points:

Code:

Plot[{x*Sin[x]}, {x, -80 Pi, 100 Pi}, PlotPoints -> 200]

or maybe fewer like 100 or so. Whatever it takes to get it right.

Thanks! That fixed it!