α . The Heat Conduction Equation in Cylindrical and Spherical Coordinates Cylindrical coordinates r,,z α ror or + r² 84² az² Spherical coordinates r,0, 10 (POT) 10² T 0² T qm ᏊᎢ + pcp at (2.7) 10 (1.2 OT ᏊᎢ 1 a² T -)+- ᏊᎢ + 2 Ər arr² sin² ² ² sine 20 (sine + q” _ƏT r 20 pcp at (2.8)