Vertical Stress Caused by a Strip Load $($Finite Width and Infinite length$)$

The vertical stress increase at point A due to strip loaded area shown in Figure $18$ can be computed as:

$=\frac{q}{}\{ta{n}^{-1}[\frac{z}{x-(\frac{B}{2})}]-ta{n}^{-1}[\frac{z}{x+(\frac{B}{2})}]-\frac{Bz[x^2-z^2-(\frac{B^2}{4})]}{[x^2+z^2-(\frac{B^2}{4}){]}^2+B^2{z}^2}\}$

The above Equation can be simplified to the form

$=\frac{q}{}[+sincos(+2)]$

The angles $$ and $$ are defined in Figure $18.$

Figure $18$ Vertical stress caused by a flexible strip load $($Note: Angles measur in counter$-$clockwise direction are taken as positive.$)$

$84$

Table $4$ Variation of $\frac{}{q}$ with $2\frac{z}{B}$ and $2\frac{x}{B}$

How can I find the row $3$ numbers in $7$

the table please solve it and also give me explanation