AP EAMCET20225 Jul 2022Morning ShiftMathematicsCircleActual
A circle is such that (x-2) +(y-2) =1 touches it for all values of . Then, the circle is
Options
- Ax^2+y^2-4 x-4 y+7=0
- Bx^2+y^2+4 x+4 y+7=0
- Cx^2+y^2-4 x-4 y-7=0
- Dx^2+y^2+4 x+4 y-7=0
Correct answer
A. x^2+y^2-4 x-4 y+7=0
Step-by-step solution
Since, the line (x-2) +(y-2) =1 touches a circle. So it is a tangent equation to a circle. Equation of tangent to a circle at (x₁, y₁ ) is (x-h) x₁+(y-k) y₁=a^2 to a circle (x-h)^2+(y-k)^2=a^2 Then, after comparing aligned & x-h=x-2 y-k=y-2 and a^2=1 & x₁= , y₁= aligned Required equation of circle (x-2)^2+(y-2)^2=1 x^2+y^2-4 x-4 y+7=0