Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Applications of Derivatives

Question:

The area bounded by the coordinate axes and normal to the curve $y=\log _e x$ at the point P(1, 0), is

Options:

1 sq. unit

2 sq. units

$\frac{1}{2}$ sq. unit

none of these

Correct Answer:

$\frac{1}{2}$ sq. unit

Explanation:

We have,

$y=\log _e x \Rightarrow \frac{d y}{d x}=\frac{1}{x} \Rightarrow\left(\frac{d y}{d x}\right)_P=1$

The equation of the normal at (1, 0) is

$y-0=-1(x-1) \Rightarrow x+y=1$

Clearly, it makes a triangle of area $\frac{1}{2}$ sq. unit with the coordinate axes.