Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Let $f:\mathbb{C}\to\mathbb{C}$ given for $f(z)=\int_0^z \frac{1-e^t}{t} dt-\ln z$ and put $g(x,y)=\text{Re}(f(z))$. While using the computer, how to determine the curve $g(x,y)=0$?

Thanks for the help.

share|improve this question
    
This is just too vague to answer... What do you know about $f$? Why don't you just solve $g(x,y) =0$ for $y$ and plot? What software do you use? –  Dirk Nov 21 '11 at 14:32
    
@Dirk: Ok, i will accept your suggestion. I tried to use maple, but had no success. Thanks –  Gardel Nov 21 '11 at 14:45
add comment

1 Answer

up vote 3 down vote accepted

Using Mathematica:

ContourPlot[With[{z = x + I y},
                  Re[EulerGamma - ExpIntegralEi[z]]] == 0,
             {x, -20, 20}, {y, -20, 20}]

exponential integral contour

share|improve this answer
    
You said you have Maple. I assume it would have the exponential integral available. Search the docs on how that function is used, as well as how to do contour plots. –  J. M. Nov 21 '11 at 17:56
    
Thank you.. one question: How do I install the Mathematica Program? He is free? –  Gardel Nov 21 '11 at 18:01
    
It's not free. There is a trial version however. –  J. M. Nov 21 '11 at 18:04
    
Another question: and analytically? –  Gardel Nov 21 '11 at 18:06
    
It's sorta kinda complicated... –  J. M. Nov 21 '11 at 18:12
show 4 more comments

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.