3 and 4 are the difficult ones

3. Obtain product of sums for the following. (a) AB+CD (b) WX + WY' X+ZYX (c) A' BC +EF DEF 4. Draw a circuit that uses only one AND gate and one OR gate to realize each of the following functions: (2.7) (a) (A+B+C+DXA+B+C + EXA+B+C+F) (b) WXYZ+VXYZ+UXYZ For each of the following circuits, find the output and design a simpler circuit that has the same output. (Hint: Find the circuit output by first finding the output of each gate, going from left to right, and simplifying as you go.) DD DD DD BD