$($a$)$ Show that the force $N_x$ for a $\frac{}{-}$ laminate takes the form

$N_x=A_{}{}_x^0+A_{xy}{}_y^0+B_{xs}{}_s$

$($b$)$ Express $A_{},A_{xy},$ and $B_{}$ in terms of transformed lamina stiffnesses $(Q_{},Q_{xy},Q_{yy},Q_{xs})$ of

the $-$ply and the ply thickness.

$($c$)$ Obtain an approximate relation between $N_x$ and ${}_x^0,{}_y^0,$ and ${}_s$ in terms of $E_1$ and $t$ for $E_1$

$E_2$ and $=45.$