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Two parabolas have the same focus. If th...

Two parabolas have the same focus. If their directrices are the x- and the y-axis, respectively, then the slope of their common chord is `+-1` (b) `4/3` (c) `3/4` (d) none of these

A

`pm1`

B

`4//3`

C

`3//4`

D

none of these

Text Solution

Verified by Experts

The correct Answer is:
A
(1) Let the focus be (a,b).
The equation are
`S_(1):(x-a)^(2)+(y-b)^(2)=x^(2)`
`S_(2):(x-a^(2))+(y-b)^(2)=y^(2)`
Common chord `S_(1)-S_(2)=0` gives
`x^(2)-y^(2)=0`
`ory=pmx`
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