Question

The length of the sub-tangent, ordinate and the sub-normal are in

• A. A.P.
• B. H.P.
• C. G.P.
• D. Arithmetico geometric progression

Answer 1

The correct option is C G.P.

Sub-tangent $=\left|y\frac{dx}{dy}\right|$

Sub-normal $=\left|y\frac{dy}{dx}\right|$

And the ordinate $=y$

As can be seen that sub-normal $\times$ sub-tangent $=(y{)}^2=$ (ordinate)${}^2$, the three are in G.P.