The loads at D', E, due to unit weight on the rail girder are (p-n)/p and n/p. The reaction at B' is {(p- n)xi+n(xi+p)}' /pi.
Describe the movement of charge carriers in forward/reverse biased p-n junction diode.
With unit load in the position shown, the load at D' is (p-n)/p, and that at E' is n/p. The moment of the load at C 'is' -n)lp. This is the equation to the dotted line RS (fig.