고체역학 (Beer) — Transformations of Stress and Strain: Problem 7.128

7.128 through 7.131 For the given state of plane strain, use the method of Sec. 7.7A to determine the state of plane strain associated with axes $x'$ and $y'$ rotated through the given angle $\theta$. 7.128: $\epsilon_x = -800 \mu$, $\epsilon_y = +450 \mu$, $\gamma_{xy} = +200 \mu$, $\theta = 25^\circ \hookleftarrow$ (clockwise rotation).