The following videos accompany the text as it relates to the Develop and Discover activity above. Please use these videos as needed.
15.5.4: Example Directional Derivative with Gradients (06:44)
15.5.6: Example Max Ascent-Descent (13:02)
15.5.7: Curve of Steepest Descent (17:40)
15.5.8: Gradient for Functions of Three Variables (08:57)
15.6.2: Tangent Planes for Implicitly Defined Surfaces with Example (11:10)
15.6.3: Example Finding Horizontal Tangent Planes (03:29)
15.6.4: Tangent Planes for Explicitly Defined Surfaces with Example (10:01)
Use the practice problems at the end Section 15.5 and 15.6 in our text to practice what you've learned this week. The problems generally increase in difficulty in each subsection. The problems towards the end of the section get increasingly more involved, so I recommend working a few problems from each of the earlier subsections, checking your answers against the back of the book, and then venturing as far as you desire.
Take a look at the learning objectives for this week (found in the overview above). After completing everything above, assess how well you feel you meet each objective (say, on a scale from 1-5, 1 being the least comfortable and 5 being confident with having met the objective). The idea here is to make a record of how you feel about each objective so that you can easily go back to it before, say, an exam or at the end of the chapter and easily see what topics you should review. It can also be helpful if you are having trouble understanding a concepts later in the course.