# NCERT Class 12-Mathematics: Chapter –6 Application of Derivatives Part 21

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## Objective Type Questions

### Choose the Correct Answer from the Given Four Options in Each of the Following Questions 35 to 39

**Question 35:**

The sides of an equilateral triangle are increasing at the rate of he rate at which the area increases, when side is is:

(A)

(B)

(C)

(D)

**Answer: (C)**

**Question 36:**

A ladder, meter long, standing on a horizontal floor, leans against a vertical wall. If the top of the ladder slides downwards at the rate of hen the rate at which the angle between the floor and the ladder is decreasing when lower end of ladder is metres from the wall is:

(A) radian/sec

(B) radian/sec

(C) radian/sec

(D) radian/sec

**Answer: (B)**

**Question 37:**

The curve has at

(A) A vertical tangent (parallel to axis)

(B) A horizontal tangent (parallel to axis)

(C) An oblique tangent

(D) No tangent

**Answer: (A)**

**Question 38:**

The equation of normal to the curve which is parallel to the line is

(A)

(B)

(C)

(D)

**Answer: (C)**

**Question 39:**

If the curve and , cut orthogonally at , then the value of is:

(A)

(B)

(C)

(D)

**Answer: (D)**

**Question 40:**

If and if *x* changes from 2 to 1.99, what is the change in

(A)

(B)

(C)

(D)

**Answer: (A)**

**Question 41:**

The equation of tangent to the curve , where it crosses axis is:

(A)

(B)

(C)

(D)

**Answer: (A)**

**Question 42:**

The points at which the tangents to the curve are parallel to axis are:

(A)

(B)

(C)

(D)

**Answer: (B)**

**Question 43:**

The tangent to the curve at the point meets axis at:

(A)

(B)

(C)

(D)

**Answer: (B)**