Evaluate the induced stresses on a rectangular plate of width $\text{'}$d$\text{'}$ and length $\text{'}1\text{'}$ by a stress function defined by

case $1$:$=A{x}^2$ case $2$:$=C,y^{-2}.$

Comment, which of the above stress function case is valid for the tensile test of a speciment.

$[5]$