圖片參考：https://webwork.math.ust.hk/webwork2_files/tmp/equations/a1/4ebc8a58404465c381b0007d584e781.png
.(a) In which direction should you walk to descend fastest? (Give your answer as a unit 2-vector.)
(b) If you start to move in this direction, what is the slope of your path?
2.
Find the equation of the tangent plane to the surface
圖片參考：https://webwork.math.ust.hk/webwork2_files/tmp/equations/64/7507e504709796df5ee79f94d9dbe21.png
0.8083 ).
更新1:
1. You are standing above the point (1,5)on the surface z=25-(3x^2+3y^2) . (a) In which direction should you walk to descend fastest? (Give your answer as a unit 2-vector.) (b) If you start to move in this direction, what is the slope of your path?
更新2:
2. Find the equation of the tangent plane to the surface z=[e^(1x)]ln(3y) at the point (-1,3,0.8083).
