iit jee 2000

If the circles x2+y2+2x+2ky+6=0 and x2+y2+2ky+k=0 intersect orthogonally , then k is

a)2 or -3/2

b)-2 or -3/2

c)2 or 3/2

d) -2 or 3/2

.........what is meant by "circles intersect orthogonally".Plz show with a diagram.

4 Answers

1
bubai bubai ·

It means that the tangents drawn at the point of contact are perp to each other.
Use condition------
2gg1+2ff1=c+c1
We get,
2k2-k-6=0
Ans.(a)

1
Avinav Prakash ·

YUP ITS (A)....SUMIT HOPE U VE UNDRSTUD WAT U WANTD

1
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11
Devil ·

Anoiother way to prove orthogonal intersection is to prove r_1^2+r_2^2=(C_1C_2)^2.

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