Question

The subtangent, ordinate and subnormal to the parabola $y^2=4ax$ at a point (different from the origin) are in

• A. AP
• B. GP
• C. HP
• D. A.G.P

Answer 1

The correct option is B

GP

$\frac{y}{\frac{dy}{dx}},y,y\frac{dy}{dx},\Rightarrow \frac{y}{\frac{4a}{2y}},y,y\times \frac{4a}{2y}\Rightarrow \frac{y^2}{2a},y,2areinGP$