## gnuplot-info

 [Gnuplot-info] Gnuplot doesn't show me the right x-axis intersection of a function From: Luigi - 2012-08-18 21:06:35 ```Hi. I was trying to plot the following function: -0.9+9.638x^(-1.394) by using the command plot y=-0.9+9.638x**(-1.394) The problem is that the intersection with the x-axis (y=0) should be at around x=5.47, but the function's plot just approaches y=0 as an asymptote. When I try to plot it with Maxima, the intersection is correct. Is there something wrong in the syntax of the command? Thanks. ```
 Re: [Gnuplot-info] Gnuplot doesn't show me the right x-axis intersection of a function From: Dr. Ing. Dieter Jurzitza - 2012-08-18 21:47:54 ```Hi Luigi, I am sure you did something wrong. First of all, your formula is erratic as it should be f(x)=-0.9+9.638*x**(-1.394) please note the "*" between the factor (9.638) and the power of x ... secondly the command plot y= something does not work, what you ought to do is either plot -0.9+9.638*x**(-1.394) w l lw 2 or say f(x)=-0.9+9.638*x**(-1.394) plot f(x) w l lw 2 to provide an example. In both cases I get the zero crossing around x=5.479 Hope this helps, take care Dieter Jurzitza On Samstag, 18. August 2012 23:06:27 Luigi wrote: > Hi. I was trying to plot the following function: > > -0.9+9.638x^(-1.394) > > by using the command > > plot y=-0.9+9.638x**(-1.394) > > The problem is that the intersection with the x-axis (y=0) should be at ************** -- ----------------------------------------------------------- | \ /\_/\ | | ~x~ |/-----\ / \ /- \_/ ^^__ _ / _ ____ / <°°__ \- \_/ | |/ | | || || _| _| _| _| if you really want to see the pictures above - use some font with constant spacing like courier! :-) ----------------------------------------------------------- ```
 Re: [Gnuplot-info] Gnuplot doesn't show me the right x-axis intersection of a function From: Jefferson Stafusa E. Portela - 2012-08-18 22:02:29 ```Hi Luigi, to what Dieter Jurzitza already said I only add that you'll see better your intersection with the x-axis if you adjust the range of the plot, for example: set xrange [0:10] set xrange [0:10] plot -0.9+9.638*x**(-1.394) w l lw 2 With the default ranges all you'll see is indeed that divergence of your function as x->0. Cheers, Jefferson On Sat, Aug 18, 2012 at 11:06 PM, Luigi wrote: > Hi. I was trying to plot the following function: > > -0.9+9.638x^(-1.394) > > by using the command > > plot y=-0.9+9.638x**(-1.394) > > The problem is that the intersection with the x-axis (y=0) should be at > around x=5.47, but the function's plot just approaches y=0 as an asymptote. > > When I try to plot it with Maxima, the intersection is correct. > > Is there something wrong in the syntax of the command? Thanks. > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > gnuplot-info mailing list > gnuplot-info@... > https://lists.sourceforge.net/lists/listinfo/gnuplot-info ```