Author Topic: Are these typos?  (Read 111 times)

Shentao YANG

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Are these typos?
« on: November 19, 2016, 10:05:43 PM »
http://www.math.toronto.edu/courses/apm346h1/20169/PDE-textbook/Chapter9/S9.1.html#mjx-eqn-eq-9.1.15
I think the coefficient for last term should be ${1 \over {2\pi c}}$ instead of ${1 \over {4\pi c}}$.

http://www.math.toronto.edu/courses/apm346h1/20169/PDE-textbook/Chapter9/S9.1.html#mjx-eqn-eq-9.1.19
I think this equation should be $(\Delta  + {{{\omega ^2}} \over {{c^2}}})v = {1 \over {{c^2}}}f(x)$ instead of  $(\Delta  + {{{\omega ^2}} \over {{c^2}}})v = f(x)$

Victor Ivrii

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Re: Are these typos?
« Reply #1 on: November 20, 2016, 10:35:52 AM »
1) Yes, it is typo. Corrected

2) No, since the wave equation is in the form
$$
\Delta u - c^{-2}u_{tt}= fe^{i\omega t}.
$$