COMEDK2013MathematicsHeights and Distances
What is the equation of the locus of a point which moves such that 4 times its distance from the X -axis is the square of its distance from the origin?
Options
- Ax²+y²-4 y=0
- Bx²+y²-4|y|=0
- Cx²+y²-4 x=0
- Dx²+y²-4|x|=0
Correct answer
B. x²+y²-4|y|=0
Step-by-step solution
Let the required point be P(x, y) . Then, aligned 4|y| &= ( .(x-0)²+(y-0)² )² . 4|y| &=x²+y² x²+y²-4|y| &=0 aligned