At (2,1), I have to find the direction where is increasing fastest.
So I did:
Next I have to find the rate of growth in this direction, so I did:
Finally I have to find the direction a this point where f is changing "least rapidly." Not sure what to do here...
I'm not quite sure what it means, hence the name of the thread. I assume the magnitude of when it is decreasing fastest is the same as when it is increasing fastest. I was thinking "zero because it isn't moving sideways" but that seems to easy. Or maybe that's the point. I dunno.