Question

The solution of $\frac{dy}{dx}=\frac{ax+g}{by+f}$ represents a circle when

• A. $a=b$
• B. $a=-b$
• C. $a=-2b$
• D. $a=2b$

Answer 1

Answer: (B)

$a=-b$

$dy(by+f)=dx(ax+g)⟹b{y}^2+2fy=a{x}^2+2gx⟹\frac{-a}{b}{x}^2+b^2-\frac{2g}{b}x+\frac{2f}{b}y=0$ represents a circle only when $a=-b$