The elevation of a mountainous terrain is given by f (x, y) =1000-(x^2)/2-4y^2 and you are at the point P(10, 5, 850).
c) If you decide to walk towards the point Q(8, 6, 824), what is the slope of your path?
d) In what direction should you walk to keep the same elevation?

Question

amistre64 · Answer

it is the direction of the vector from (10,5,850)  to (8,6,824) right?

amistre64 · Answer

subtract the points to get the vector between them

anonymous · Answer

Is it the direction derivative from point P to Q?

amistre64 · Answer

12,  5, 850
-8,-6,-824
----------
t <4, -1 ,26>

amistre64 · Answer

the derivative is for the slope at a point right?  this is the slope between 2 pts if I read it right

anonymous · Answer

And then find the value of the vector?

anonymous · Answer

How come the website is so laggy nowadays

amistre64 · Answer

should we convert this to spherical coords?

amistre64 · Answer

if your not on firefox, or maybe even chrome; it bogs down

anonymous · Answer

i am using firefox. For C i think i got it now,,how about D?

amistre64 · Answer

elevation i believe is 850

amistre64 · Answer

so you can walk in the x and y direction to keep the same altitude;

amistre64 · Answer

maybe the tangent plane to z = 850?  kinda guesing at that one

amistre64 · Answer

$$\frac{1000-(x^2)}{2-4y^2}$$ is this the equation?

amistre64 · Answer

$$1000 - {x^2\over 2}-4y^2$$ maybe?

amistre64 · Answer

the gradient is: <-x,-8y> if its the second one; but not sure how that helps

anonymous · Answer

Sorry I went to take care some stuff