ExamBro
ExamBro
AP EAMCET · Maths · Circle

If the circles \(x^2+y^2-2 x+4 y+c=0\) and \(x^2+y^2+2 x-\) \(4 y+c=0\) have four common tangents, then

  1. A \(\mathrm{c} < 0\)
  2. B \(-2 < \) c \( < 2\)
  3. C \(0 < \) c \( < 5\)
  4. D \(\mathrm{c}>0\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(0 < \) c \( < 5\)

Step-by-step Solution

Detailed explanation

The given equation of circle is as follows :- \(x^2+y^2-2 x+4 y+c=0\) ...(i) \(x^2+y^2+2 x-4 y+c=0\) ...(ii) Radius and centre of circle (i) is \(r_1=\sqrt{(-1)^2+(2)^2-c}=\sqrt{5-c}\) and \(c_1=(+1,-2)\) Radius and centre of circle (ii) is…