Economics习题答案 (Seventh Editionby, Michael Parkin).pdf

tionship is positive because x and y move in the same PARKIN direction: As x increases, y increases. 5b. The slope increases as x increases. Slope is equal to the ECONOMICS change in y divided by the change in x as we move along the curve. When x increases from1 to 2 (a change of 1), y increases from 1 to 4 (a change of 3), so the slope is 3. But when x increases from 4 to 5 (a change of 1), y increases from 16 to 25 (a change of 9), so the slope is 9. S o l u t i o n s t o 5c. The taller the building, the bigger is the cost of building it. The higher the unemployment rate, the higher is the O d d - n u m b e r e d crime rate. The longer the flight, the larger is the amount of fuel used. P r o b l e m s 7. The slope equals 8. The slope of the curve at the point where x is 4 is equal to the slope of the tangent to the c