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The distance of two points P and Q on th...

The distance of two points P and Q on the parabola `y^(2) = 4ax` from the focus S are 3 and 12 respectively. The distance of the point of intersection of the tangents at P and Q from the focus S is

A

8

B

6

C

9

D

12

Text Solution

Verified by Experts

The correct Answer is:
B

If `P(at_(1)^(2),2at_(1))` and `Q(at_(2)^(2),2at_(2))`, and `T(at_(1)t_(2),a(t_(1)+t_(2)))`
Thus, we have `ST^(2) = SP xx SQ = 3 xx 12 = 36`
`:. ST = 6`
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