How does an increase in foreign demand for U. S. exports affect the IS curve? b) How does an increase in government purchases (say, on education or defense) affect the IS curve? c) How do largecuts to personal income taxesaffect short-runoutput? d) Suppose the government cuts social security benefits to pay for the tax cuts in part c. How does the combined policy affect short-run output if you assume the permanent income consumption model holds? Whatif you assume a life-cycle consumption model holds, instead?