9.Suppose the government enacts a $10 billion tax eut and that the people who save money from this tax cut will spend 70% of it and save the rest. This generates $10(07)=$7 billion of extra income for other people. Assume these people also spend 70% of their extra income, and that these transactions continue. Let A(n) be the accumulated amount of speading, in billions of dollars, that has occurred after n such transactions. For example A(1) is the amount of spending that has occurred after the first group of people bas spent its money, so A)-10(0.7)- $7 bilion. A(2) is the amount of spending that has occurred after the first and second groups of people have spent their money,so Al2) S10(0.7+S7(0.7)- $11.9 billion, in the following graph: (a) Express A(n) in sigma notation (b) Calulate A(3), (4), and A(5) (c) Estimate the total spending created by this tax cut by calculating the accumulated spending for at least 10 of these transactions. Interpret your answer in terms of the given graph