Assume that the normal strains (x and (y for an element in plane stress (see figure) are

Question:

Assume that the normal strains (x and (y for an element in plane stress (see figure) are measured with strain gages.
(a) Obtain a formula for the normal strain (z in the z direction in terms of (x, (y, and Poisson's ratio v.
(b) Obtain a formula for the dilatation e in terms of (x, (y, and Poisson's ratio v.