Compute the volume of a tetrahedron. (a) Illustrate the tetrahedron that has vertices at (0,0,0),(2,0,0),(0,3,0),(0,0,6), in Cartesian coordinates. The top face of the tetrahedron is part of the plane 6x+ 4y+2z=12, or equivalently, z=6−3x−2y. This tetrahedron sits inside a box with side lengths 2,3 and 6 . The volume of this box is V=2×3×6=36 cubic units. The volume of the tetrahedron must be some fraction of this. (b) What do you think this fraction is? (c) Set up a double integral that will compute the volume of this tetrahedron. (d) Evaluate the double integral. Suggestion: work slowly and at each step check your algebra and arithmetic before proceeding. (e) Set up a triple integral that will compute the volume of this tetrahedron. (f) Evaluate this triple integral as an iterated integral so that you integrate first with respect to z. After integrating with respect to z, your computation should connect with your computations in part (d). After this point it is not necessary to repeat these computations.
