Problem

If the length of subnormal is equal to length of subtangent at any point

(3, 4)

on the curve

y = f(x)

and the tangent at

(3, 4)

y = f(x)

meets the coordinate axes at

A

and

B

, then maximum area of the

\Delta OAB

where

O

is origin, is a.

\frac{45}{2}

\frac{49}{2}

\frac{25}{2}

\frac{81}{2}