Chapter 2 concluded that the quanti

Chapter 2 concluded that the quantities of X and Y that a person chooses depend on that person’s preferences and on the details of his or her budget constraint. If we knew a person’s preferences and all the economic forces that affect his or her choices, we could predict how much of each. good would be chosen. We can summarize this conclusion using the demand function for some particular good, say, X: Quantity of X demanded ¼ dX ðPX , PY , I; preferences) (3.1) This function contains the three elements that determine what the person can buy—the prices of X and Y and the person’s income (I)—as well as a reminder that choices are also affected by preferences for the goods. These preferences appear to the right of the semicolon in Equation 3.1 because, for most of our discussion, we assume that preferences do not change. People’s basic likes and dislikes are developed through a lifetime of experience. They are unlikely to change as we examine their reactions to relatively short-term changes in their economic circumstances caused by changes in commodity prices or incomes. The quantity demanded of good Y depends on these same general influences and can be summarized by Quantity of Y demanded ¼ dY ðPX , PY , I; preferences) (3.2) Preferences again appear to the right of the semicolon in Equation 3.2 because we assume that the person’s taste for good Y will not change during our

Homogeneity
One important result that follows directly from Chapter 2 is that if the prices of X
and Y and income (I) were all to double (or to change by any identical percentage),
the amounts of X and Y demanded by this person would not change. The budget
constraint
PXX þ PYY ¼ I (3.3)
is the same as the budget constraint
2PXX þ 2PY Y ¼ 2I (3.4)


CHANGES IN INCOME
As a person’s total income rises, assuming prices do not change, we might expect
the quantity purchased of each good also to increase. This situation is illustrated in
Figure 3.1. As income increases from I1 to I2 to I3, the quantity of X demanded
increases from X1 to X2 to X3 and the quantity of Y demanded increases from Y1 to
Y2 to Y3. Budget lines I1, I2, and I3 are all parallel because we are changing only
income, not the relative prices of X and Y. Remember, the slope of the budget
constraint is given by the ratio of the two goods’ prices, and these prices are not
changing in this figure. Increases in income do, however, make it possible for this
person to consume more; this increased purchasing power is reflected by the outward
shift in the budget constraint and an increase in overall utility.

Hasil (Bahasa Indonesia) 1:

Bab 2 menyimpulkan bahwa jumlah X dan Y yang seseorang memilih tergantung pada preferensi seseorang itu dan rincian nya atau anggaran kendala. Jika kita tahu preferensi seseorang dan semua kekuatan-kekuatan ekonomi yang mempengaruhi pilihan Nya, kami dapat memperkirakan berapa banyak masing-masing. baik akan dipilih. Kita bisa meringkas kesimpulan ini menggunakan fungsi permintaan untuk beberapa baik tertentu, mengatakan, jumlah X: X menuntut ¼ dX ðPX, PY, saya; preferensi) (3.1) fungsi ini mengandung tiga unsur yang menentukan apa yang orang dapat membeli-harga X dan Y dan pendapatan seseorang (I) — serta pengingat bahwa pilihan juga dipengaruhi oleh preferensi untuk barang. Preferensi ini muncul di sebelah kanan titik koma dalam persamaan 3.1 karena, untuk sebagian besar pembahasan kita, kita berasumsi bahwa preferensi tidak berubah. Dasar orang suka dan tidak suka dikembangkan melalui pengalaman seumur hidup. Mereka tidak mungkin untuk mengubah sementara kita meneliti reaksi mereka relatif jangka pendek perubahan dalam keadaan ekonomi yang disebabkan oleh perubahan dalam harga-harga komoditas atau pendapatan. Kuantitas menuntut y baik tergantung pada umum yang sama pengaruh dan dapat diringkas oleh kuantitas Y menuntut ¼ dY ðPX, PY, saya; Preferensi preferensi) (3.2) lagi muncul di sebelah kanan titik koma dalam persamaan 3.2 karena kita berasumsi bahwa seseorang rasa untuk baik Y tidak akan berubah selama kitaHomogeneityOne important result that follows directly from Chapter 2 is that if the prices of Xand Y and income (I) were all to double (or to change by any identical percentage),the amounts of X and Y demanded by this person would not change. The budgetconstraintPXX þ PYY ¼ I (3.3)is the same as the budget constraint2PXX þ 2PY Y ¼ 2I (3.4)CHANGES IN INCOMEAs a person’s total income rises, assuming prices do not change, we might expectthe quantity purchased of each good also to increase. This situation is illustrated inFigure 3.1. As income increases from I1 to I2 to I3, the quantity of X demandedincreases from X1 to X2 to X3 and the quantity of Y demanded increases from Y1 toY2 to Y3. Budget lines I1, I2, and I3 are all parallel because we are changing onlyincome, not the relative prices of X and Y. Remember, the slope of the budgetconstraint is given by the ratio of the two goods’ prices, and these prices are notchanging in this figure. Increases in income do, however, make it possible for thisperson to consume more; this increased purchasing power is reflected by the outwardshift in the budget constraint and an increase in overall utility.