Here is a log of updates, starting in January 2016, to the list of corrections I maintain for the third edition of Mathematical Methods in the Physical Sciences by Mary L. Boas.

August 27, 2022 (contributed by John Reid)
Page 69: In problems 17 and 18, an arbitrary real constant can be added to the right-hand side.
Page 169: In (12.37), the equation $$\textrm{V} = \begin{pmatrix} \phantom{-}8 & -6 \\ -6 & \phantom{-}9 \end{pmatrix}$$ should have the letter V in upright font, not slanted font.
Page 783: The solution to problem 5.46 should exclude the case that $$x=y=0$$.
November 17, 2021 (contributed by Scott Webster)
Page 807: In the solution to Problem 14.4.8, the Laurent series valid when $$|z|<1$$ should be $$-5 +\frac{25}{6}z -\frac{185}{36}z^2+\cdots$$. The printed solution mistakenly has $$175$$ instead of $$185$$ in the numerator of the coefficient of $$z^2$$.
November 9, 2021 (contributed by David Calvis)
Page 374: In Problem 5, the instructions imply that the period $$2l$$ is equal to $$1/60$$, so the hint should say that the value of $$l$$ is $$1/120$$, not $$1/60$$.
September 13, 2019 (contributed by Edward Price)
Page 41: In Problem 22, for “$$n$$ is an even integer” read “$$s$$ is an even integer”.
May 20, 2019 (contributed by Yoshinao Hirota)
Page 264: In Example 3, the density should be stated to be constant. The same comment applies to Example 4 on page 265, to Problem 1 on page 267, to Problem 26 on page 270, to Problem 4 in the Miscellaneous Problems on page 273, and to Problem 17 on page 274.
May 10, 2019 (contributed by Yoshinao Hirota)
Page 525: At line -5, the parenthetical remark should say “from (8.15)” instead of “from (8.11)”.
March 29, 2018 (contributed by David Calvis)
Pages 588–591: The discussion of solutions of Bessel’s equation has an implicit assumption that $$p\ge 0$$, so $$-p \le 0$$.
March 11, 2018 (contributed by Tim Leishman)
Page 604: In Problem 4, change $$\lim\limits_{x\to 0} J_{p}(x) /N_{p}(x)$$ (the limit of the quotient) to $$\lim\limits_{x\to 0} J_{p}(x) N_{p}(x)$$ (the limit of the product).
December 6, 2017 (contributed by Adelaide Deley)
Page 124: At line -6, for “point to pint” read “point to point”.
November 30, 2017 (contributed by Alec English)
Page 499: At line 5, for “nd” read “and”.
November 30, 2017 (contributed by Tim Leishman)
Page 457: In addition to the previously known correction to Example 5, the notation can be clarified by putting a subscript $$0$$ on the variables in lines 1, 4, and 7: namely, $$(x_0,y_0,z_0) = (-1, \sqrt{3}, -2)$$ and $$(r_0,\theta_0,z_0) = (2, 2\pi/3, -2)$$ and $$(r_0,\theta_0, \phi_0) = (2\sqrt{2}, 3\pi/4, 2\pi/3)$$.
May 4, 2017 (contributed by Brandon Morrison)
Page 671: In addition to the previously known correction to the equation in the last paragraph on the page (the equation should be set equal to zero), the symbol $$d$$ in the first denominator should be changed to a partial derivative symbol $$\partial$$.
September 4, 2016 (contributed by Steven Blake)
Page 602: In the integral on the left-hand side of the displayed equation at the bottom of the page, the notation is confusing and technically wrong. The notation $$d(r/a)$$ indicates that the integration variable is $$r/a$$ (equivalently $$x$$), so the limits of integration should be $$0$$ and $$1$$, not $$0$$ and $$a$$. In the integral on the right-hand side of the equation, the integration variable is explicitly $$r$$, so the limits of integration are correctly $$0$$ and $$a$$.
February 10, 2016 (contributed by Tim Leishman)
Page 458: Two lines after the third displayed equation on the page, delete the closing parenthesis preceding the period. In other words, replace the expression $$-\mathbf{e}_r/r^2)$$ by $$-\mathbf{e}_r/r^2$$ without the trailing parenthesis.
January 28, 2016 (contributed by Jean-Philippe Suter)
Page 356: In the first displayed equation, the expression $$2\ln x \big|_0^1$$ should be $$2\ln x \big|_0^\pi$$ (but the conclusion that the integral diverges to infinity is unchanged).
Page 624: In the second line following equation (2.14), the expression that arises when $$y=30$$ is actually $$\tfrac{1}{2}e^0 - \tfrac{1}{2}e^0$$, not $$e^0-e^0$$, but is equal to $$0$$ as claimed.
Page 634: In the line of text following equation (4.4), for “are are” read “are”.