P. 525, Equation 11.44

The equation should be

$c_n = \frac{2}{L_x \left(e^{n \pi L_y/L_x} - e^{-n \pi L_y/L_x} \right)} \int_0^{L_x} f(x) \sin \frac{n \pi x}{L_x} dx.$

Return to errata.