Starting with the logic diagram for the 7 4x283 in Figure 6-87, write a logic expression for the S3 output in terms of the inputs, and prove that it does indeed equal the fourth sum bit in a binary addition as advertised. You may assume that c0 = 0 (i.e., ignore c0).
![370_6022eae6-e350-40c0-ae2a-bd8c366b81cb.png](https://secure.tutorsglobe.com/CMSImages/370_6022eae6-e350-40c0-ae2a-bd8c366b81cb.png)