A soil sample did not pass a triaxial test when the deviator stress was $200$ kPa with a confining pressure of $100$ kPa. If the confining pressure had been $200$ kPa for the same sample, what would the deviator stress at failure have been for $($a$)$ c $=0$ using both graphical and analytical methods, and $($b$)\backslash$phi u $=0$ using the graphical method?"