4. In a PID controller, the relationship between the measurement variable and the control variable is assumed to be linear as shown in Equation 8.13. If instead, the relationship is MV =f (CV^2), how would you modify the basic equation to linearize the relationship? I have difficulty understanding what you have wrote. can you please make it legible and not sure why you replaced "e"with "E"- is there a reason for it?

Thank you and can you explain how you came up with it?