zyy+(1/z)xx+2=0.
A=(18(a2+1)zxaz+18(−a2+1)zya14(a+1)2za14(a−1)2za−18(a2+1)zxaz−18(−a2+1)zya),
B=(18(−a2+1)zxaz2+18(a2+1)zyaz14−a2+1az14−a2+1az−18(−a2+1)zxaz2−18(a2+1)zyaz)