Recent content by Sux

Sorry I said partial derivatives don't exist, I wanted to say they are not continuous in (0,0). I have calculated f_{y} and it is not continuous in (0,0). How can you calculated the condition for differentiability that have written? Thanks!

Homework Statement Hello, I can't find any way to prove if this funtion is or isn't differentiable in if (x,y)=(0,0) : {f(x,y)=\displaystyle\frac{x^{3}}{x^{2}+y^{2}}} if (x,y) \neq(0,0) f(x,y)=0 if (x,y)=(0,0) The Attempt at a Solution Partial derivatives don't exist...

Yes, stellar "extinction" is the loss of flux or brightness due to interstellar dust. Here you have it: http://nedwww.ipac.caltech.edu/level5/Mathis/Mathis1.html" Thanks for the answers.

Hi! In this problem I have to calculate the distance to a cefeide star, I know visual magnitude, m_{v}, his magnitude in B range, m_{b} and its period, P. Well, if I ignore extinction, I can calculate the distance with M_{V}: m_{v}=M_{V}+5log(\frac{r}{10})+A_{v} Where A{v} is visual magnitude...