The signal flow diagram for a certain feedback control system is shown in the figure.
Now consider the following set of equations for the nodes
1. x2 = a1x1 + a9x3
2. x3 = a2x2 + a8x4
3. x4 = a3x3 + a5x2
4. x5 = a4x4 + a6x2
Which of the following is correct?
1
1, 2 and 3
2
1, 3 and 4
3
2, 3 and 4
4
1, 2 and 4