1. For the following generating functions list all formal products in which the exponent sums to 4. (a) f(x) = (1+r + x 4 ) 2 (1 + x + x) 2 (b) g(x)=(1+x + x + x + x +x + ...) 3. 2. Build a generating function for ar, the number of integer solutions to the following equation: e1e2e3+ 4 = r with e; > 0, e2, e4 odd, and e4