At a point in a stressed body, the strains, related to the coordinate set xyz, are given...

At a point in a stressed body, the strains, related to the coordinate set xyz, are given by

Determine (a) the strain invariants; (b) the normal strain in the x’ direction, which is directed at an angle θ=30^o from the x axis; (c) the principal strains and (d) the maximum shear strain.