Question

u = tan
${ - 1}^{?}$

$( x ^{2} + y ^{2} )$

​

Answer 1

Answer:

${x}^{2} + {y}^{2} = {(x - y)}^{2} + 2xy = {(x + y)}^{2} - 2xy$

Answer 2

Answer:

$x2+y2=(x−y)2+2xy=(x+y)2−2xy$