WeBWorK Standalone Renderer

Use the contour diagram of $f$ to decide if the specified directional derivative is positive, negative, or approximately zero.

1. At the point $(-1,1)$ in the direction of $(-\vec{i} + \vec{j})/\sqrt{2}$ ,

2. At the point $(-1,1)$ in the direction of $(-\vec{i} - \vec{j})/\sqrt{2}$ ,

3. At the point $(0,2)$ in the direction of $\vec{j}$ ,

4. At the point $(0,-2)$ in the direction of $(\vec{i} - 2\vec{j})/\sqrt{5}$ ,

5. At the point $(1,0)$ in the direction of $- \vec{j}$ ,

6. At the point $(-2,2)$ in the direction of $\vec{i}$ ,

(Click graph to enlarge)

You can earn 50% partial credit for 4 - 5 correct answers.