Chapter 14.4, Problem 27E

In Exercises 23–28, which of the following vectors gives the direction of the gradient vector at point A on the contour diagram? The scales on the x- and y-axes are the same.

$\stackrel{\to }{i}-\stackrel{\to }{i}$

$\stackrel{\to }{j}-\stackrel{\to }{j}$

$\stackrel{\to }{i}+\stackrel{\to }{j}$

$\stackrel{\to }{i}-\stackrel{\to }{j}$

$-\stackrel{\to }{i}-2\stackrel{\to }{j}$

$-2\stackrel{\to }{i}-\stackrel{\to }{j}$