A/ i-Find and classify the equilibrium point(s) of the following nonlinear system * =y- (z+u) y=z+u+y-x =-z+sgn[x-1+ u=-u+sgn[x+1+ sgn(z)] +0.5 sgn(u)] -0.5. ii-The scheme shown in Fig.Q1-A represents a satellite control system with rate feedback provided by a gyroscope. Draw the phase portrait of the system, and determine the system's stability. U 0 0 s+a = Fig.QI-A i-Find and classify the equilibrium point(s) of the following nonlinear system * =y- (z+u) y=z+u+y-x =-z + sgn[x - 1+ sgn(z)] + 0.5 u=-u+sgn[x + 1 + sgn(u)] -0.5. ii-The schema