Exercise 4.2: Different Boolean expressions can be equivalent to each other. Draw the circuit for each of the following 3 expressions and experimentally construct the Truth table for each one by trying all possible input combinations and observing the output. Compare your results between the 3 different circuits. What do you conclude? (it will be much easier if you use the same a, b switches for all 3 circuits) a) not(not(b) and (a or b)) written also as b (a b b) a .6 a. b a b c) a b Exercise 4.3: An XOR gate (called exclusive-or has the following truth table: b (a XOR b) a) Write the Boolcan expression zrepresenting a XOR b b) Using AND gates, OR gates and inverters, draw the circuit that is equivalent to an XOR gate. Then build the circuit on your simulator, and experimentally construct the truth table for your circuit and compare it to the truth table above. c) Construct the circuit implementing the expression Z (a. b) a) ((a b) b) and experimentally construct its truth table. What do you conclude