Here is a list of topics not to be missed when doing a review for Exam 2:
3.2. Flow lines: what they are, how to calculate them
3.3 div: calculation and geometrical/physical intuitive interpretation as sink/source
3.4 curl: calculation and geometric/physical intuitive interpretation as tendency to rotate
3.5 del notation (be able to recognize and use it, including for div and curl)
3.7 Taylor series: be able to write the linear approximation, or the quadratic approximation for a function of 1,2,3 variables at a given point.
Critical points, the Hessian matrix, the second derivative test.
3.6 Laplacian: notation and calculation
4.1 Line integrals: calculation
4.2 Recognize regions which are (or not) open, connected, simply connected.
4.3, 4.4 Know the statements of the three main theorems and be able to use them in problems.