If P = (1, 0), Q = (-1, 0) and R = (2, 0) are three given points, then the locus of a point S satisfying the relation
SQ2+SR2=2SP2 is
A straight line parallel to y-axis
Let S(x, y), then
(x+1)2+y2+(x−2)2+y2=2[(x−1)2+y2]
⇒ 2x +1 + 4 - 4x = - 4x + 2 ⇒ x = -32
Hence it is a straight line parallel to y-axis.