--> //initializations

--> q=120 //KN/m (live load)
 q  = 

   120.


--> x=2 //m (coordinate)
 x  = 

   2.


--> z=3.5 //m (coordinate)
 z  = 

   3.5


--> //calculation

--> nz=((2*q)/(%pi*z))*(1/(1+(x/z)^2))^2 //(vertical stress at point P)
 nz  = 

   12.403915


--> //results

--> printf('vertical stress at point P=%f',nz) //KN/m^2
vertical stress at point P=12.403915
