combine pdf in linux

PDF Arranger is a small python-gtk application, which helps the user to merge or split PDF documents and rotate, crop and rearrange their pages using an interactive and intuitive graphical interface. 

https://github.com/pdfarranger/pdfarranger

small figure occupied whole page

 \usepackage{float}

\begin{figure}[H]

\end{figure}

TOYS

digital piano

https://www.roland.com/ca/products/fp-30x/

https://www.korg.com/us/products/digitalpianos/d1/

Compare weather anywhere

https://weatherspark.com/

https://thestackhouse.com/

// print painting

https://www.stuffedsafari.com/Hansa-Stuffed-Animals-and-Plush-Animals-s/14.htm

https://www.christmascentral.com/set-of-3-handcrafted-plush-mallard-duck-stuffed-animals-13-5/

https://www.christmascentral.com/set-of-2-lifelike-handcrafted-extra-soft-plush-canada-goose-stuffed-animals-17-5-31068644/

// goose

A teacher-created site

 A to Z Teacher Stuff is a teacher-created site designed to help teachers find online resources more quickly and easily. Find lesson plans, thematic units, teacher tips, discussion forums for teachers, downloadable teaching materials, printable worksheets, emergent reader books, themes, and more.

http://atozteacherstuff.com/

Average over a sphere surface

 The surface integral of the function $f$ over the surface $S$ is denoted by

\[ \int\int_S f dS \]

$dS$ is the area of an infinitesimal piece of the surface $S$.

Average over the sphere is

\[ <f> = \frac{1}{4\pi} \int_0^{2\pi} d\phi \int_0^{\pi} f \sin(\theta)d\theta ,\]

where $dS=\sin(\theta)d\theta d\phi$. This can be seen as a weight average, the weight is surface area.

\[ <\cos^2(\theta)>=1/3 \]

\[<\sin(\theta)>=2/3.\]

rigidity and larmor radius

 

From:https://w3.iihe.ac.be/~aguilar/PHYS-467/PA3.pdf