$$( \frac{ xP }{ xq } )P+Q \times ( \frac{ yR }{ yq } )r+q \times ( \frac{ zP }{ zr } )p+r \times xP2 \times yq2 \times zr2$$
$\frac{P_{2}qq_{2}r_{2}xyzr^{2}+Ppq^{2}+QRr^{2}+rP^{2}}{qr}$
$P_{2}q_{2}rr_{2}yz$
