AP EAMCET201824 Apr 2018Morning ShiftMathematicsCircleActual
The number of common tangents to the circles x^2+y^2-4 x-2 y+k=0 and x^2+y^2-6 x-4 y+l=0 , having radii 2 and 3 respectively, is
Options
- A4
- B2
- C3
- D1
Correct answer
B. 2
Step-by-step solution
Given circle are, gathered x^2+y^2-4 x-2 y+k=0 Centre c₁(2,1) and r₁=2 x^2+y^2-6 x-4 y+l=0 gathered Centre c₂(3,2) and r₂=3 aligned c₁ c₂ & = (2-3)^2+(1-2)^2 & = 1+1 = 2 c₁ c₂ & < r₁+r₂ aligned So, circles have two common tangents.