Question

What is "Locus" ?

"The Locus of a point equidistant from the 2 fixed points is the straight line which is perpendicular bisector of the segment joining the fixed points"

What does the above statement mean?

Answer 1

hey friend ,

locus is the path traced by the point under given condition..

we can also say that path teaced by moving point.

Answer 2

Locus is the path of a variable generic point (x,y) that satisfies given conditions in 2-dim. space (or that of (x,y,z) in 3-d space.)

Locus is the set of all points in space that satisfy the given conditions. 
For example   Y axis is the locus of all points with x coordinate being 0.

Let two fixed points be A and B. Point P (x,y) is equidistant from both A and B.  So midpoint O of AB satisfies the condition. Let COB be the perpendicular bisector of AOB.

Every point P on the perpendicular bisector COD is equidistant from A and B.  We know this, as APB is an isosceles triangle always.

So the set of all points P or the curve joining all points P satisfying the condition (of equal distance from AB ie., AP = PB) is the perpendicular bisector.

COD is the locus.