Hello,

ich have some function, where:

f(x,y)=(2xy)/(k^2+2xk+2yk)+(2xy)/(k^2+2xk+2yk+4xy)+ln((k^2+2xk+2yk)/(k^2+2xk+2yk+4xy)), where k is a constant.

If k<<x and k<<y, then

f(x,y)=(2xy)/(2xk+2yk), WHY??????

I understand, that k^2=0, but what about the second and third fraction? Why have they been dissapeared?

Thank you for any clue,

Mary