Wikipedia sez: The natural logarithm of $x$ is often written "$\ln(x)$", instead of $\log_e(x)$ especially in disciplines where it isn't written "$\l...

Can we affirm that: $0 \times \ln(0) = \ln(0^0) = \ln(1) = 0$? The problem is $\ln(0)$ is supposed to be undefined but it works

What is the volume of a 4D sphere? I've seen so many sites that would have answered this question, but all of them have so many numbers that some peo...

Second Update: I see that some answers that reference my image are more closely answering my question. Here is a second image to clarify my point. Take th...

If a polyhedron is made only of pentagons and hexagons, how many pentagons can it contain? With the assumption of three polygons per vertex, one can prove...

I have an external 5T drive where I want to copy my files (about 22GB). When copying the files everything runs well for a while and then it gets really sl...

What is the difference between /opt and /usr/local directories and what kind of programs should be installed to them? I referred to Linux File-system Hier...

I downgraded from libreoffice 5.4.x to go back to 5.1.x in the repositories now I can't run any libreoffice program. How can I fix this? What I did t...

When I try to install tor I get: Reading package lists... Done Building dependency tree Reading state information... Done Package tor is not available, bu...

I am using Handbrake to rip a DVD to a MKV. The filesize for a ~5GB .VOB rip is a nearly 2GB .MKV. Is there a program in Ubuntu that shrinks MKV's? I...