JEE Main2005MathematicsCircleActual
A circle touches the x -axis and also touches the circle with centre at (0,3) and radius 2. The locus of the centre of the circle is
Options
- Aan ellipse
- Ba circle
- Ca hyperbola
- Da parabola
Correct answer
D. a parabola
Step-by-step solution
Equation of circle with centre (0,3) and radius 2 is x^2+(y-3)^2=4 Let locus of the variable circle is ( , ) It touches x -axis. It equation (x- )^2+(y- )^2= ^2 Circles touch externally aligned & ^2+( -3)^2 =2+ & ^2+( -3)^2= ^2+4+4 & ^2=10( -1 / 2) aligned Locus is x^2=10(y-1 / 2) which is parabola.