### Updates and Typos

This page maintains a list of errata for the printed book.

p. 30: The first rule should be ln(x^{y}) = y ln x, i.e., x to the y power, not simply ln(xy) as it is in the book.

p. 51: The chain rule example at the top of the page is (x^2)^3 so that is x^6 and d/dx is 6x^5. The book says d/dx((x^2)^3) = 3(x^2)*2x = 6x^3 -- this is wrong because it is missing a "^2" term after (x^2). It should be d/dx((x^2)^3) = 3(x^2)^2*2x = 6x^5. (Thanks to Prof. Huang for catching this one.)

p. 105: "At m=50, the income elasticity of x1* = (0)(140/6.25) = 0" should be "at m=140" since this value of income is the initial value . This doesn't make any difference in this case since the income elasticity is zero at m=50 and m=140. (Thanks to Aileen Hoffman.)

p. 152: The substitution and income effects should be switched in the penultimate paragraph. So, the book says, "The substitution effect is 16 2/3 - 20 5/6 = - 4 1/6. The income effect is 20 5/6 - 25 = - 4 1/6." It should say, "The income effect is 16 2/3 - 20 5/6 = - 4 1/6. The substitution effect is 20 5/6 - 25 = - 4 1/6." (Thanks to Prof. Heavey's students, Chris Busuttil and Max Fink and his student assistant Yang Li for pointing this out.)

p. 179: The m1 term in the constraint is missing a (1 - TaxBreak), so it should be: (1 - TaxBreak)BeneficiaryCon + p2DonorCon <= (1 - TaxBreak)m1 + m2

I corrected this equation in the Excel workbook.

p. 311: I switched the key relationship between average and marginal cost. The book says, "Whenever an average curve is above the marginal curve, the marginal curve must be rising. Conversely, whenever the average is below marginal, the marginal must be falling." That is not right.

Here is the correct statement: "Whenever a marginal curve is above an average curve, the average curve must be rising. Conversely, whenever the marginal is below the average, the average must be falling."

p. 362: Under "max," at the very bottom of the page, instead of just "L," it should be "L, q" because the firm gets to pick both L and q as choice variables in the constrained version of the input profit max problem. Also, while not a mistake, I should have pointed out that an easy way to connect the shutdown rule on the input and output sides is to note that shutdown occurs when w > ARP(L), which can be rewritten as wL > TRP, which can be translated to the output side as TVC > TR and, dividing both sides by output, AVC > P. (Thanks to Prof. Widdows for this correction and suggestion.)

p. 431: The demand and supply functions derived from the given inverse demand and supply functions incorrectly have price in the denominator. Below, the equations on the left are printed in the book, but they should have P as shown in the equations on the right. (Thanks, Rebeca.)

p. 458: "Although the red triangle that represents the deadweight loss is shorter (because the new equilibrium price is lower than before), it is much wider." The latter part is true, the triangle is wider because quantity falls by more when D is more elastic, but the the height of the triangle remains the same. The height is the amount of the tax and it is constant.

Although I am not tracking and updating web addresses in the book, the excellent History of Economic Thought web site mentioned three times has a new URL:

p. 143 and p. 540: homepage.newschool.edu/het/ is gone, but it can be accessed via the Wayback Machine at web.archive.org/web/20100302181941id_/http://homepage.newschool.edu/~het/

p. 471: homepage.newschool.edu/het/profiles/schump.htm is at the link above (click Alphabetical Index and then scroll down to Schumpeter).

BTW, as Wikipedia helpfully proclaims at the very top, the aptly named Wayback Machine is "Not to be confused with the WABAC machine of Peabody's Improbable History" -- which I never knew was spelled WABAC . . . and I apologize to those too young and those who never saw Mr. Peabody and his pet boy Sherman or Boris Badenov and Natasha Fatale, all waaaaay better than modern cartoon fare!

Last Update: 24 Jan 2015