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Saturday, September 2, 2023

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/

Wednesday, August 30, 2023

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.

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

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




Wednesday, June 7, 2023