4. (8 marks) Construct a single neural network unit that takes two boolean inputs, a and a2, and outputs the value of the logical proposition aa2 Like the units we designed in class for the boolean AND and OR functions, your neural network unit can use a fixed input, set to 1, in addition to the two boolean inputs ai and a2 The unit should use a threshold activation function such that it outputs 1 if the weighted sum of inputs is positive and outputs 0 otherwise. (a) Draw your neural network unit, indicating the weights you have chosen for each input (b) For each of the input combinations below, show the calculations involved in com puting the weighted sum of inputs and the output of your neural network unit: ii. a,-1, a2 = 0