Question

The length of sub tangent at any point of the curve log $y=25$x is ________.

• A. Zero
• B. Proportional to y
• C. Proportional to x
• D. Constant

Answer 1

The correct option is D Constant

$lny=25x$

$\therefore \frac{dx}{dy}=\frac{1}{25y}$

Length of subtangent $=|y\frac{dx}{dy}|$

$=|y\left(\frac{1}{25y}\right)|$

$=\frac{1}{25}$

Hence, the answer is option (D).