Let the equation of line having intercept a, b, on coordinates axes is
+ = 1 ... (i)
∴ This intercept line meet the coordinate axes at P(a,0) and Q (0, b), respectively
Since, Eq. (i) passes through (4, 2)
∴
+ = 1 ... (ii)
Since, (h,k) is circumcentre of Δ OPQ. Therefore (h,k) is the mid point of PQ
∴ h =
=
and k =
=
... (iii)
⇒ a = 2h and b = 2k
∴ From Eq. (ii) and Eq. (iii), we get
+ = 1
⇒
+ = 1
∴ Locus of the circumcentre is
+ = 1