Questions tagged [complex]

Questions about using complex numbers in Mathematica. This includes basic arithmetic, functions of complex numbers, plotting complex functions, and dealing with branch cuts.

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Using DeleteCases to ignore term of Product

I'd like to calculate $\int_{-\infty}^{\infty}\mathrm{d}x/(1+x^6)$ through a variation of the residue formula, which is $\int_{-\infty}^{\infty}f(x)\mathrm{d}x=2\pi i\sum \text{Res }f$ for Residues in ...
343 views

I evaluated ...
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Plotting a dispersion curve with complex wavevectors [duplicate]

I want to reproduce a dispersion curve from P. Zou's thesis found here: http://www.ipd.anl.gov/anlpubs/2001/06/39620.pdf on Pg. 31, Eq. 2.13. The problem is, the code below only gives values for the ...
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Please explain this unexpected code snippet behavior [duplicate]

Consider a function that maps a complex function z->f(z) to it's multivariable counterpart (x,y)->f(x,y) ...
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Why is PolyLog[] giving weird answers for ordinary values? [duplicate]

Possibly related to this question, but it seems slightly different: Strange behaviour of PolyLog Function Wikipedia says that for real s, z<1 should be real. So I was confused when MMa returned: ...
140 views

Why does this integral have a complex result

I wanted to find the normalization of distribution F2 . ...
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Simplifying complex expresion (without ComplexExpand or User defined rules) [closed]

Many times, I've struggled with simplifying complex expressions, such as this extraordinarily simple expression, and Mathematica wont do it: ...
152 views

Plot a complex function as a vector along a curve

I have y a function of x and a parameter k. I use but don't really understand Plot[Evaluate@Table[y[x,k],{k,{.01,.02,3,4,6}}],{x,.171,300},PlotRange etc. to ...
332 views

Evaluate complex exponential expression [closed]

I am trying to evaluate the modulus of the following expression. The expected result is 1.3. However, I tried Abs, ComplexExpand but still couldn't get it. Can anyone help me out? Thanks. 1/(1+e^(...
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Integrate is giving imaginary solution

I read through some of the previous posts on imaginary answers popping up due to integrals, but I was unable to find a solution to my similar problem. I have the following integral (reduced to its ...
732 views

Real and Imaginary matrix

I have a 2 by 2 matrix T: {{x, y}, {-y, x}} where x is the real part of some complex number and y is the imaginary part of something complex number. Let's say z1 = ...
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What does mean |sin(z)|<=1? [closed]

I already know that the magnitude of sin(z) its equal to sqrt(sin^2(x)+sinh^2(y))
283 views

How to convert this complex number to exponential form? [closed]

I have $Z = {\frac{2+i}{2-i}}$. I need to write it in exponential form, i.e. $Z = r*e^{i{\phi}}$. I simplified the given example to ${\frac{3 + 4i}{5}}$, i.e. $a={\frac{3}{5}}, b={\frac{4}{5}}$. ...
302 views