In two consolidated drained triaxial compression tests conducted under constant cell pressures of $\backslash$sigma cell$1$ and $\backslash$sigma cell$2$ on sand

samples, observed maximum deviator stress were $\backslash$sigma d$1$ and $\backslash$sigma d$2,$ respectively. Find shear stress at failure on the failure plane,

orientation of that plane with respect to vertical and shear strength parameters using assigned inputs.