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CHAPTER 14
Boundary-Value Problems in Other Coordinate Systems
In the previous chapter we utilized Fourier series to solve boundary-value problems that were described in rectangular coordinates. But if we wish to find, say, temperatures in a circular plate, circular cylinder, or sphere, we would naturally describe the problem in polar coordinates, cylindrical coordinates, or spherical coordinates, respectively. We will see that the method of separation of variables in the last two coordinate systems leads to Fourier–Bessel series and Fourier–Legendre series.