1.

If three distinct normals are drawn from `(2k, 0)` to the parabola `y^2 = 4x` such that one of them is x-axis and other two are perpendicular, then `k =`A. `klt1`B. `kgt1`C. `kle1`D. `kge1`

Answer» Correct Answer - B
The equation of any normal to `y^(2)=4x`, is
`y=mx-2m-m^(3)" …(i)"`
`rArr" "m^(3)+2m(1-k)=0rArrm=0, m=+-sqrt(2(k-1))`
For three normals to be real and distinct, we must have
`2(k-1)gt1`


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