고체역학 (Beer) — Transformations of Stress and Strain: Problem 7.145

7.145 The strains determined by the use of the rosette shown during the test of a machine element are \[ \epsilon_1 = +600 \mu \quad \epsilon_2 = +450 \mu \quad \epsilon_3 = -75 \mu \] Determine (a) the in-plane principal strains, (b) the in-plane maximum shearing strain.