Task $6$:

A $45$ strain rosette was placed on an implanted plate and the following strains were measured: ${}_a=350({10}^{-6}),{}_b=-200({10}^{-6}),{}_C=-400({10}^{-6}).$ Determine $($a$)$ the principal strain ${}_1$ and the angle of transformation and $($b$)$ the maximum inplane shear strain.