KCET2009MathematicsCircle
The locus of the mid points of the chords of the circle x²+y²=4 which subtend a right angle at the origin is
Options
- Ax²+y²=1
- Bx ²+ y ²=2
- Cx+y=1
- Dx+y=2
Correct answer
B. x ²+ y ²=2
Step-by-step solution
Let mid point of the chord AB is C ( x ₁, y ₁ ) . In COB , 4 = BC OB array ll & 1 2 = BC 2 & BC = 2 array Using Pythagoras theorem OB ²= OC ²+ CB ² (2)²= x ₁²+ y ₁²+( 2 )² x ₁²+ y ₁²=2 Hence, locus of mid point of chord is x²+y²=2