The differential equation determines a family of circles with
- A.variable radii and a fixed centre at
- B.variable radii and a fixed centre at
- C.fixed radius 1 and variable centres along the -axis
- D.fixed radius 1 and variable centres along the -axis
Show answer and solution
Correct option: C
Solution
Separate variables: y dy/√(1-y²) = dx. Integrate both sides: -√(1-y²) = x + C, so √(1-y²) = -(x+C). Squaring: (x+C)² + y² = 1. This is a family of circles with radius 1 and centres at (-C, 0), which vary along the X-axis.
[AIEEE 2007]