1.

Find the equations of the hyperbola satisfying the given conditions :Foci `(0,+-sqrt(10))`, passing through (2,3)

Answer» Here, Foci of hyperbola `= (+-sqrt10,0)`
That means the transverse axis of the hyperbola is `Y`-axis.
So, the equation will be of the type,
`y^2/a^2-x^2/b^2 = 1->(1)`
Also, `c = sqrt10`
In a hyperbola, `c^2 = a^2+b^2`
Putting value of `c`,
`=> (sqrt10)^2 = a^2+ b^2`
`=>b^2 = 10-a^2`
Putting vallue of `b^2` in (1),
`y^2/a^2-x^2/10-a^2 = 1->(2)`
As hyperbola is passing through `(2,3)`, `x=2` and `y=3` should satisfy (2).
`So, 9/a^2-4/(10-a^2) = 1`
`=>9(10-a^2)-4a^2 = a^2(10-a^2)`
`=>90-9a^2-4a^2 = 10a^2 - a^4`
`=>a^4-23a^2+90 = 0`
`=>a^4-18a^2-5a^2+90 = 0`
`=>(a^2-18)(a^2-5) = 0`
`=> a^2 = 18 and a^2 = 5`
But, `a^2` can not be greater than `c^2`.
`:.a^2 = 5`
`b^2 = 10 - 5 = 5`
Putting values of `a^2` and `b^2` in (1),
`y^2/5-x^2/5 = 1`


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