Question

If (a, b) is the centre of a circle passing through the origin, then its equation is-

• A. x² + y² – ax – by = 0
• B. x² + y² + 2ax + 2by = 0
• C. x² + y² – 2ax – 2by = 0
• D. x² + y² + ax + by = 0

Answer 1

Answer: (C)

x² + y² – 2ax – 2by = 0

Answer 2

r = $\sqrt{\alpha^{2} + \beta^{2}}$

Equation (x – a)² + (y – b)² = a² + b²