If a root candidate does not satisfy the equation, it can be used to shorten the list of remaining candidates.

The infinitesimal difference in internal energy between the initial and final state will then satisfy the above equation.

This is found to satisfy the equation (in the interval )

Under standard assumptions the flight path angle satisfies the equation:

If there exists a function , then will be the smallest g satisfying the above equation.

If we keep the coefficients constant and vary the points that satisfy the equation we create a line.

There may be points where either or does not exist and yet u satisfies the equation in an appropriate sense.

Hence an additional current will be drawn from the generator so as to satisfy the equation.

This algorithm is slow in practice because we need to search many such numbers, and only a few satisfy the strict equation.

We can now state that and satisfy the equation from the first step of the BW algorithm.