Let P(a,b) and Q(c,d) are any two points. Given, OP=OQ i.e. √a2+b2=√c2+d2 Squaring on both sides, ‌a2+b2=c2+d2 . . . (i) ‌‌‌‌‌R={((a,b),(c,d)):a2+b2=c2+d2} ‌R(x,y),S(1,−1),OR=OS ‌ This gives ‌OR=√x2+y2‌ and ‌OS=√2 ⇒√x2+y2=√2 ⇒x2+y2=2(‌ Squaring on both sides ‌) ∴‌‌S={(x,y):x2+y2=2}