# Tagged Questions

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

0answers
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### why the result not contain imaginary, I?

Good day, First of all, sorry if my coding in this forum has mistake. I already learned it and this is the best try from me. May anyone help me troubleshoot my problem below. ...
1answer
1k views

### Stereographic Projection

Say I want to represent points of the complex plane in the sphere $\Bbb S^2$ using stereographic projection. That is, the Riemann sphere: Specifically, it would be nice to be able to: Given the ...
0answers
35 views

### Can you define “| |” to be the same as “Abs[ ]”? [duplicate]

When calculating the modulus of a complex number in Mathematica, the standard (and probably least-ugly) way of doing it is by using the Abs[ ] function. When doing ...
2answers
240 views

### NIntegrate and Integrate giving different results for ill-behaved function

I'm trying to integrate the following function with Mathematica 8: $$I(a,b)= \int_0^1 \mathrm{d}x\int_0^1\mathrm{d}y \,\theta(1-x-y) \frac{1}{x a^2-y(1-y)b^2},$$ where $\theta$ is the Heaviside ...
0answers
5 views

3answers
60 views

### how to take complex conjugate of a real variable

I have a function defined as follows: g[θ_] := 1/k (Exp[-I δ0] Sin[δ0] + 3 Exp[I δ1] Sin[δ1 Cos[θ] + 5/2 Exp[I δ2 (3 (Cos[θ])^2 - 1)) and I compute ...
1answer
65 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 = ...
1answer
53 views

### What makes imaginary parts show up?

If I define a function using alpha[y_, d_] := 2 ArcCos[1 - (2 y)/d] Then if $y$ and $d$ are equal, the result is $2\pi$ : ...