Question Number 148991 by gsk2684 last updated on 02/Aug/21

The largest value of k for which the circle x^2 +y^2 =k^2 lies completely in the interior of the parabola y^2 =4x+16 ?

Answered by mr W last updated on 02/Aug/21

x^2 +4x+16−k^2 =0 Δ=4^2 −4(16−k^2 )≤0 k^2 ≤12 ⇒−2(√3)≤k≤2(√3)