Consider the equation 5y 7y 4y ft Express this equation i
     Consider the equation: 5y + 7y + 4y = f(t)  Express this equation in state space form along with the output. Define your variables clearly. 
  
  Solution
Consider the second-order equation
 5 ¨y + 7 y + 4y = f (t)
 Solve it for the highest derivative:
 ¨y = 1
 5
 f (t)  4
 5
 y  7
 5
 y
 Now define two new variables, x1 and x2, as follows: x1 = y and x2 = y. This implies
 that  x1 = x2 and
  x2 = 1
 5
 f (t)  4
 5
 x1  7
 5
 x2

