![Quaternions: Why is the angle $\frac{\theta}{2}$? [duplicate]](https://edu.smbbmcl.edu.pk/uploads/quaternions-why-is-the-angle-frac-theta-2-duplicate_720.jpg)
Quaternions: Why is the angle $\frac{\theta}{2}$? [duplicate]
The equation for creating a quaternion from an axis-angle representation is $$x'= x \sin\left(\frac \theta 2\right)$$ $$y' = y \sin\left(\frac \...
04 Apr 2026 1 READS
UFW blocking upnp port mapping
I'm attempting to use portmapper-2.1.1 (https://github.com/kaklakariada/portmapper) to get a upnp mapping to my ubuntu 16.04LTS machine. I've go...
04 Apr 2026 1 READS
What books must every math undergraduate read?
I'm still a student, but the same books keep getting named by my tutors (Rudin, Royden). I've read Baby Rudin and begun Royden though I'm u...
04 Apr 2026 1 READS
Problems with USB in Ubuntu 20.04
After update from Ubuntu 18.04 (where everything worked correctly) to Ubuntu 20.04 I have a problem with USB: 08:59:20 kernel: usb 1-3: 2:1: cannot get fr...
04 Apr 2026 1 READS
Solve $x^3 +3x -4 =0$ in Real numbers
Solve $x^3 +3x -4 =0$ in Real Numbers. I know the answer is 1 but i want the solution. if you solve it with decomposition, explain how did you find what t...
04 Apr 2026 1 READS
How can I find my hardware details?
Is there any built-in software or terminal method allowing me to view the hardware profiles on my system? Windows equivalent of such a feature would be De...
04 Apr 2026 1 READS
How to resetup Brother MFC-J480DW for scanning after it changed its IP?
Every time I restart my router or for other reasons my printer changes its IP and I can't print or scan anymore. Setting up the printer is straightfo...
04 Apr 2026 1 READS
Matrix for reflection about the line $y = \tan (\theta) \, x$
How would I show that a reflection about the line $y = \tan (\theta) \, x$ is the following? \begin{pmatrix} \cos 2\theta & \sin 2\theta \\ \sin 2\the...
04 Apr 2026 1 READS
Solving the following Volterra Integral Equation?
How do I solve the following Volterra, non-homogeneous, $1st$ kind Integral Equation : $$ \dfrac{x^2}{2}=\int_0^x (1-x^2+t^2)u(t) dt$$ I know I cannot app...
04 Apr 2026 1 READS
Samba not working under ubuntu 21.10 impish
my samba has stopped working on Ubuntu 21.10 impish not sure when it started but I get this on start: $ sudo service smbd restart [sudo] password for user...
04 Apr 2026 1 READS
