$2\mathrm{.}5$ a$.$ Using the Hebb rule, find the weights required to perform the following classi$-$ fications: Vectors $(1,1,1,1)$ and$-(1,1,-1,-1)$ are members of the class $($and therefore have target value $1)$; vectors $(1,1,1,-1)$ and $(1,-1,-1,1)$ are not members of the class $($and have target value $-1).$

b$.$ Using each of the training x vectors as input, test the response of the net.