Calc help!

[ga14]

How would you calculate the directional derivative of a point on a contour map, with respect to different directions?
This is the contour map:
http://www.math.duke.edu/education/ccp/materials/mvcalc/yosemite-alt/contours.html

I need to calculate the directional derivative from the point (5000ft, 4000ft) using the scale on the axis (which corresponds to 367, 445 on the map), in the directions due N, NE, W, and SW.

Do you just take the change in the y's over the change in the x's?

Thanks for any help.

 

[StageLeft]

a squared plus p cubed = derivative of the exponent

 

[RossGr]

I couldn't get your drawing to come up. But....

To get directional derivatives from a contour map I would simply count the number of coutour lines crossed when moving from point a to b when moving in a given direction (North, south etc) compute rise/run and that should be your number.

 

[ga14]

http://www.math.duke.edu/education/ccp/materials/mvcalc/yosemite/contours.html

There's another version of the contour map that should work.

What would the distance X that I traveled be? would it be the distance of a unit vector? in this case 1000 ft?