Laplace’s equation in the Polar Coordinate System

represent the heat and wave equations in the polar coordinate system. For the heat equation, the solution u(x,y t)˘ r µ satisfies ut ˘k(uxx ¯uyy)˘k µ urr ¯ 1 r ur ¯ 1 r2 uµµ ¶, k ¨0: diffusivity, whereas for the wave equation, we have utt ˘c 2(u xx ¯uyy)˘c 2 µ urr ¯ 1 r ur ¯ 1 r2 uµµ ¶ c ¨0: wave velocity. 3

  System, Coordinates, Equations, Waves, Velocity, Polar, Wave velocity, Equation in the polar coordinate system, In the polar coordinate system