Suppose that the cost to ship an envelope is a function of its weight. For any
envelope up to 1 ounce, the charge is a stamp that costs $0.47. For an envelope over
1 ounce and up to 2 ounces, the charge is $0.68. Finally, for an envelope over 2
ounces and up to 3 ounces, the charge is $0.89. What are the practical domain and
range of this function?