Solution:
Let P (h, k) represent any point on the locus
And let the coordinates of A and B be given by (0, 0) and (h, 0).
Where,
PA = 3PB
Upon squaring both the sides we get,
h2 + k2 = 9k2
h2 = 8k2
By replacing (h, k) with (x, y)
Therefore, the locus of point is x2 = 8y2