The circle \(x^2+y^2-6 x-10 y+p=0\) neither intersects nor touch the coordinate axes and the point \((1,4)\)…

The circle \(x^2+y^2-6 x-10 y+p=0\) neither intersects nor touch the coordinate axes and the point \((1,4)\) lies inside the circle. Then the range of possible values of ' \(p\) ' is
  1. \(23 < p < 25\)
  2. \(25 < p < 29\)
  3. \(21 < p < 23\)
  4. \(12 < p < 21\)

Solution

The equation of given circle is \(\begin{array}{rlrl} x^2+y^2-6 x-10 y+p & =0 \\ \Rightarrow & \quad(x-3)^2+(y-5)^2 & =34-p \end{array}\) \(\therefore\) The point \((1,4)\) lies inside the circle, so \(\begin{array}{ll} & 1+16-6-40+p < 0 \\ \therefore \quad & p < 29 \quad \ldots (i) \end{array}\) \(\therefore\) The circle neither intersects nor touches the coordinate axis, then \(\begin{array}{lll} & r=\sqrt{34-p} < 3 \Rightarrow 34-p < 9 \\ \Rightarrow & p > 25 \quad \ldots (ii) \\ \text {and } & r=\sqrt{34-p} < 5 \\ \Rightarrow & 34-p < 25 \\ \Rightarrow & p > 9 \quad \ldots (iii) \end{array}\) from in equalities Eqs. (i), (ii) and (iii), we get \(25 < p < 29\) Hence, option (b) is correct.

Asked in: AP EAMCET 2020 (18 Sep Shift 2)

Practice more Circle questions on Aicharya