(adsbygoogle = window.adsbygoogle || []).push({}); Determined to finish off my assignment!!

Firstly, it's 2:50 am here and I'm NOT going to sleep until I finish this assignment off!! I have few remaining ones and I'd be glad if someone could help me out so I can go to sleep...

Please consider this question(and the one I posted below);

f:R^2-->R is defined by f(x,y)=lxyl where lxyl is absolute value of xy

(a)Show that f is differentiable at (0,0)

For this, I think using definition of 'differentiable' is almost impossible, so I'm thinking should I use the theorem which says the function is differentiable if all of partial derivatives exist, and each entry in jacobian matrix exists in a neighbourhood of the point and continuous at that point.

But... partial derivative of something inside absolute value?... also to show each entry in jacobian is continuous... do i use epsilon delta argument??

(b)Show that there is no disc B((0,0);delta) throughout which f has all of its directional derivatives

This one scares me off...

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# Homework Help: Determined to finish off my assignment

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