Answer:
C(xi, yj) is the cost of changing symbol xi from X into symbol yj from Y. In this example, the costs for I, D, and C are given as 0.5, 0.4, and 1.2, respectively. Therefore, to find the cost of changing a symbol xi from X into symbol yj from Y, we can use the following formula:
C(xi, yj) = 0.4 if xi = yj
C(xi, yj) = 1.2 if xi ≠ yj
For example, to change the first symbol of X (which is 'a') into the first symbol of Y (which is 'b'), we have xi = 'a' and yj = 'b'. Since xi ≠ yj, the cost of this operation is C(xi, yj) = 1.2. Similarly, to change the second symbol of X (which is 'a') into the third symbol of Y (which is 'b'), we have xi = 'a' and yj = 'b'. Since xi ≠ yj, the cost of this operation is also C(xi, yj) = 1.2.