1.

If a hyperbola centred at origin, has one of its directrix as x=2.Also ordinate of one of the end point of a latus rectum is 12. Then find its eccentricity.

Answer»

`3/2`
`4/3`
`2`
`8/3`

Solution :EQUATION will be `x^2/a^2-y^2/b^2=1` its DIRECTRIX is `x=2 =a/e` also given `b^2/a=12=a(e^2-1)`
`rArr 12=2e. (e^2-1)`
`e^3-e-6=0`
`rArr (e-2)xx(e^2+2e+3)=0`
`rArr` e=2


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