Re: Directional Derivative

I finally clued into the fact that Latex is only working with [tex] tags, so I retyped everything to make it easier.

19.

P: (0,0)

20.

<1,-1> is the direction we should move away from the origin for z to change most rapidly.

The max rate of change is

I still have yet to figure out how to solve the last question in problem #20.

Any help with where I'm stumped or in just reviewing the work I have completed so far would be appreciated. Thanks.

Re: Directional Derivative

The "directional derivative" in the direction of **unit** vector, v, is the dot product of grad f and v. In particular, the derivative will be 0 is that dot product is 0 which means v must be **perpendicular** to grad f. What vectors are perpendicular to <1, -1>?

Re: Directional Derivative