The locus of mid point of the chords of the circle x2+y2-2x-6y-10=0 pa...
Solution:
Finding the equation of circle:
The given equation can be written as:
x2-2x+y2-6y=10
Completing the square, we get:
(x-1)2+(y-3)2=20
Hence, the given equation represents a circle with center (1,3) and radius √20.
Finding the equation of chords:
The chord passing through the origin has equation y=mx. Substituting this in the equation of circle, we get:
x2+(mx)2-2x-6mx-10=0
Simplifying, we get:
(x2+m2x2-2mx)+(-2x-6mx-10)=0
The x-coordinates of the points of intersection of this chord with the circle are the roots of this quadratic equation. By Vieta’s formulas, the sum of the roots is:
x1+x2=2m/m2+1
The midpoint of this chord has coordinates ((x1+x2)/2, (y1+y2)/2), which can be expressed in terms of m as:
((2m/m2+1)/2, m(2m/m2+1)/2)
Simplifying, we get:
(x,y)=(m2-1/2m, m/2(m2+1))
Eliminating m:
The equation of the locus of the midpoints can be obtained by eliminating m from the equations for x and y. We have:
x=(m2-1)/2m
y=m/2(m2+1)
Eliminating m, we get:
x2+y2-xy-x-y=0
Simplifying, we get:
(x-y)2-(x+y)=0
Substituting z=x-y, we get:
z2-z=0
Solving for z, we get z=0 or z=1.
Substituting back for z, we get two lines:
x-y=0 and x+y-1=0.
Hence, the locus of midpoints is given by the equation:
x2+y2-x-3y=0
Therefore, option 'B' is correct.
The locus of mid point of the chords of the circle x2+y2-2x-6y-10=0 pa...
The equation of the chord if mid point is given--
T=S1. let midpoint be (h,k)
xh+yk-(x+h)-3(y+k)-10=h2+k2-2h-6k-10
passing through origin (0,0)
-h-3k = h2+k2-2h-6k
h2+k2-h-3k = 0
putting h,k= x,y
x2+y2-x-3y = 0