Final answer:
The question relates to applying Stokes' theorem to a given triangular path for the purpose of evaluating a line integral in vector calculus.
Step-by-step explanation:
The student's question pertains to the application of Stokes' theorem in vector calculus to a triangle path in three-dimensional space. Stokes' theorem relates the surface integral of the curl of a vector field over a surface to a line integral around the boundary of the surface. In this case, the triangle path specified by the points (0,0,0), (2,1,1), and (2,0,2) defines such a boundary, and lies within the plane z=x-y. To use Stokes' theorem, we need to parametrize the triangle path or choose a surface that the triangle encloses, calculate the curl of the given vector field, and then evaluate the line integral of the vector field along the given path or the surface integral of the curl over the surface enclosed by the path.
Note: The provided excerpts from the book appear to discuss forces and tension in the context of Newton's laws, which are not directly relevant to the application of Stokes' theorem in the context of this question. Therefore, that information will be disregarded in formulating an answer.