How can I plot loglog(x,y) with an xlim and ylim?

I am trying to graph using loglog(x,y), however I am running into problems with a Negative data ignored message. Here is some of my code:

xlim([1,1000000])

ylim([0.000000000001,0.00001]);

a= [2300*10^(-9), 223.0*10^(-9), 5.30*10^(-12), 20.0*10^(-12), 2.19*10^(-12)];

b=[8.7, 135, 3289, 51290,10219];

y= a(1).*exp(-x./b(1));

loglog(x,y,'b');

Thanks!

Answer 1

[Mischa Kim]

Christopher, move the xlim and ylim commands after the loglog command. Make sure that x > 0.

[Christopher]

Mischa, I did what you said and moved it after the loglog command, and it worked! No more error, however, it won't graph the entire curve.. it stops abruptly at x=10^1. Thanks!

[Mischa Kim]

How is x defined in your code? Note that with the xlim and ylim commands you define the axis limits. You need an additional command to define x values, e.g., using logspace

 x = logspace(0,3,100);  % define x: 100 data points btw. 10^0 and 10^3
 a = [2300*10^(-9), 223.0*10^(-9), 5.30*10^(-12), 20.0*10^(-12), 2.19*10^(-12)];
 b = [8.7, 135, 3289, 51290,10219];

 y = a(1).*exp(-x./b(1));

 loglog(x,y,'b');
 xlim([1,1e6])
 ylim([1e-12,1e-5]);

[Christopher]

Great! It worked, I forgot to define x!! Thanks again!