Equation Icon  729x2Φ ′′k′′+ 3888x Φ ′′k′+ (1782 + 54x2)Φ ′′k + 144xΦ ′k + (90 + x2)Φk [ ( ℰ) ′′′′ ( ℰ )′′′ 2 ( ℰ )′′ = const.× 243 π-k − 810- πk- + 18(135-+-2x--) πk- ρ x ρ x2 ρ ( ) ′ ( ) ] 30-(162 +-x2) πkℰ x4-+-30(162-+-x2)- πℰk- − x3 ρ + x4 ρ . (396 )