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### Why ArcTan[1, 0. I ] yields -1.5708+0. I?

Bug introduced in 5.2 or earlier and persisting through 12.0.0 Why ArcTan[1, 0. I ] yields -1.5708+0. I ? The result should ...
63 views

### Where is the mistake in computing the particular eigenvector of the following DFT Matrix?

I have the following matrix (the DFT Matrix for N = 3) W = \frac{1}{\sqrt{3}}\begin{pmatrix} 1 & 1 & 1 \\ 1 & e^{-\frac{i 2 \pi}{3} } & e^{\frac{i 2 \pi}{3} } \\ 1 & e^{\frac{...
87 views

### Incorrect result for the region of convergence of a simple integral

Bug persisting at least through version 11.3.0 The standard Gaussian integral Integrate[Exp[-a x^2], {x,-Infinity,Infinity}] returns ...
200 views

### Series expansion gives incorrect result

Bug introduced after 10.4 and persisting through 11.3.0 Mathematica 11.1.1.0 tells me that ...
142 views

### Improper ParametricPlot3D result when using certain complex numbers

Bug introduced in 8 or earlier and persisting in 11.1 This is more out of curiosity than for any project that I'm working on. I was experimenting with the ParametricPlot3D and put in the following ...
267 views

### Symbolic and numeric limit disagreeing on branch cut of ArcTan

Bug introduced after 8.0.4 and before 9.0.1 and fixed in 11.1.0. Investigating comments to my previous question lead me to the following problem: ...
327 views

### Integrate and NIntegrate disagreeing over branch cut of Sqrt?

Bug introduced after 8.0.4 and before 9.0.1, and fixed in 11.1.0. In Mathematica 10.2 I'm trying to integrate this piecewise continuous function, but Integrate and ...
335 views

### Strange behavior of Limit in Mathematica 9 and 10 (bug?)

fixed in 10.1 Consider a complex logarithm where the branch cut is defined along the negative axis. Then for $r$ and $\eta$ real and positive we can write \$ \lim_{\eta \to 0} \log(-r+ i \eta) = log (...