If tangents `P Qa n dP R` are drawn from a variable point `P` to thehyperbola `(x^2)/(a^2)-(y^2)/(b^2)=1,(a > b),` so that the fourth vertex `S` of pa
If tangents `P Qa n dP R`
are drawn from a variable point `P`
to thehyperbola `(x^2)/(a^2)-(y^2)/(b^2)=1,(a > b),`
so that the fourth vertex `S`
of parallelogram `P Q S R`
lies on the circumcircle of triangle `P Q R`
, then the locus of `P`
is
`x^2+y^2=b^2`
(b) `x^2+y^2=a^2`
`x^2+y^2=a^2-b^2`
(d) none of these
A. `x^(2)+y^(2)=b^(2)`
B. `x^(2)+y^(2)=a^(2)`
C. `x^(2)+y^(2)=a^(2)-b^(2)`
D. none of these
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1 Answers
Correct Answer - C
The fourth vertex of the parallelogram lies on the circumcircle.
Therefore, the parallelogram is cyclic,
i.e., the parallelogram is a rectangle,
i.e., the tangents are perpendicular.
Therefore, the locus of P is the director circle.
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