z=f(x,y)= (cos y) - (cos x)(adsbygoogle = window.adsbygoogle || []).push({});

u are at the origin and want to hike to point (4pie,0,0). U want to get to 4pie,0,0 by hiking a route that alway keeps you at the same elevation. what is the lenght of this route?

I ploted the graph and I already know the route that will keep me at the same elevation from origin to 4pie,0,0 but how do I find the lenght of that route??

As for the second part

Your second route always moves along the gradient. Determine such a route of minimal lenght, assuming you start hiking in the positive x direction. What is the length? If you cannot find and exact answer, then determine an upper bound and a lower bound bbetween which the actual lenght must lie.

I have no clue on doing the second part.

I need some serious help because this will determine my final grade so be clear and help me as much as u can. Thanks

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Need with 3d graph question

**Physics Forums | Science Articles, Homework Help, Discussion**