JEE Main2014MathematicsCircleActual
For the two circles x^2+y^2=16 and x^2+y^2-2 y=0 , there is/are
Options
- Aone pair of common tangents
- Btwo pair of common tangents
- Cthree pair of common tangents
- Dno common tangent
Correct answer
D. no common tangent
Step-by-step solution
Let, x^2+y^2=16 or x^2+y^2=4^2 radius of circle r₁=4 , centre C ₁(0,0) we have, x^2+y^2-2 y=0 aligned & x^2+ (y^2-2 y+1 )-1=0 or x^2+(y-1)^2 =& 1^2 aligned Radius 1, centre C ₂(0,1) aligned & |C₁ C₂ |=1 & |r₂-r₁ |=|4-1|=3 & |C₁ C₂ | < |r₂-r₁ | aligned no common tangents for these two circles.