Question Number 87988 by M±th+et£s last updated on 07/Apr/20
$${solve}\:{the}\:{PDE} \\ $$$$\mathrm{1}−{Z}={px}+{py}−{q}\sqrt{{pq}} \\ $$$$\mathrm{2}−{Z}={px}+{qy}+{sin}\left({p}+{q}\right) \\ $$$$\mathrm{3}−{p}\left(\mathrm{1}+{q}^{\mathrm{2}} \right)={q}\left({Z}−{a}\right) \\ $$$$\mathrm{4}−{Z}={xyp}^{\mathrm{2}} \\ $$