(1-k2⁢cos2⁡ϕ)⁢ⅆ2⁡wⅆ⁡ϕ2+k2⁢cos⁡ϕ⁢sin⁡ϕ⁢ⅆ⁡wⅆ⁡ϕ+(h-ν⁢(ν+1)⁢k2⁢cos2⁡ϕ)⁢w=0,