Re: The graph of (x + 2)^(1/5) + 4 not plotted correctly

*To*: mathgroup at smc.vnet.net*Subject*: [mg103962] Re: The graph of (x + 2)^(1/5) + 4 not plotted correctly*From*: Mike Bryniarski <melondisco at gmail.com>*Date*: Tue, 13 Oct 2009 23:22:33 -0400 (EDT)*References*: <868306d90910120643u7f1c2299v2cd1845508dc85b7@mail.gmail.com>

The link you posted does not seem to relate to your problem. you wanted to show : Plot[ (x + 2)^(1/5) + 4 , {x, -4, 4}] I tried plotting the function in your subject and not surprisingly it did not plot correctly. the issue is taking the fifth root of x on Mathematica can result in a complex number. (This can bee seen under possible issues on the Power page in the documentation) Example: in: (x + 2)^(1/5) + 4 /. x -> -3 out: 4 + (-1)^(1/5) The most obvious way (at least for me) to overcome this is to perform some algebra on the function to eliminate the fractional power and plot it in ContourPlot instead: ContourPlot[(y - 4)^5 == x + 2, {x, -4, 4}, {y, 0, 6}] This is the result I assume you were looking for. On Oct 13, 7:22 am, victor chg <kindlych... at gmail.com> wrote: > Here is the link to the image:http://tinypic.com/view.php?pic=veae6u&s= =4 > > Victor Chg > -------------------------------------- > Neuroscience Research Institute, Peking University, Beijing, P.R.China > 100038