L_s=\int_o^{\infty} L_{\lambda} d\lambda = 4\pi R_s^2 \int_0^{\infty} F_{\lambda} d\lambda what does this mean?

This equation relates the luminosity of a star to various vectors and physical Moduli.

It’s concepts are taught in basic astrophysics classes –usually in grade 6 or 7, depending on which school you attend.

Well it is wrtitten in LaTex, so I opened the [LaTex Formula] box and copied it in.

This is what it is supposed to look like.   

$$4\pi r^2$$     is the surface area of a sphere.

BUT I really don't know what this is about.

One of our higher level mathematicians might be able to help you more.  

$$L_s=\int_o^{\infty} L_{\lambda} d\lambda = 4\pi R_s^2 \int_0^{\infty} F_{\lambda} d\lambda$$