find fxx,fyy,fxy for f(x,y)= e^-x/y
partial diffrentiation
:)

Question

mr.math · Answer

Do you know how to find a partial derivative of first order, (i.e $f_x$ or $f_y$)?

mr.math · Answer

In order to find a partial derivative of a function with respect to one variable you have to consider the other variable(s) as constants.

mr.math · Answer

For the given function $\large f(x,y)=\frac{e^{-x}}{y}$, if this what you wrote,
$$f_x=-{e^{-x} \over y}$$

mr.math · Answer

You can see here that we dealt with the variable as a constant. Similarly,
$$f_y=-{e^{-x} \over y^2}$$

anonymous · Answer

you just have to grind it til you find it.  no quick tricks.  for example 
$$\frac{\partial}{\partial y}e^{-\frac{x}{y}}=\frac{xe^{-\frac{x}{y}}}{y^2}$$

mr.math · Answer

We're working on different functions, which is good for the questioner :D

anonymous · Answer

oooooooooooh i could be wrong.  i took it to be 

$$f(x,y)=e^{-\frac{x}{y}}$$

mr.math · Answer

I'm glad you took the difficult one :P

anonymous · Answer

thanks, notice i didn't continue for 
$$f_{yy}$$

mr.math · Answer

Neither did I. I will let her try it herself.

anonymous · Answer

@moya let us know if you get stuck, and also which function you have

mr.math · Answer

and @Moya, what kind of name is Moya?