# NCERT Solutions for Class 12 Maths Exercise 6.5

NCERT Solutions for Class 12 Maths Exercise 6.5 AOD – Application of Derivatives (Maxima and Minima) in Hindi Medium as well as English Medium for all students using latest NCERT Books Solutions. Download CBSE Solutions Apps updated as per the latest CBSE Syllabus 2019-20 for CBSE and other Boards.

 Class 12: Maths Application of Derivatives Exercise 6.5

## NCERT Solutions for Class 12 Maths Exercise 6.5

### Class 12 Maths Chapter 6 Exercise 6.5 Solutions in English

NCERT Solutions for Class 12 Maths Chapter 6 Exercise 6.5 AOD – Application of Derivatives in English Medium Maxima and Minima. Click here to go back to Class 12 Maths Chapter 6 all exercises or go for Hindi Medium Solutions.

#### Class 12 Maths Chapter 6 Exercise 6.5 Solutions in Hindi

NCERT Solutions for Class 12 Maths Exercise 6.5 AOD – Application of Derivatives in Hindi Medium free to use online. Click here to go back to Class 12 Maths Chapter 6 all exercises or go for English Medium solutions.

Go to Hindi Medium or English Medium solutions

##### Questions From Board Papers
1. An inverted cone has a depth of 10 cm and a base of radius 5 cm. Water is poured into it at the rate of 3/2 c.c. per minute. Find the rate at which the level of water in the cone is rising when the depth is 4 cm.
2. A swimming pool is to be drained for cleaning. If L represents the number of litres of water in the pool t seconds after the pool has been plugged off to drain and L = 200(10 − t)². How fast is the water running out at the end of 5 sec. and what is the average rate at which the water flows out during the first 5 seconds?
3. A spherical ball of salt is dissolving in water in such a manner that the rate of decrease of the volume at any instant is proportional to the surface area. Prove that the radius is decreasing at a constant rate.
4. The length of a rectangle is increasing at the rate of 3.5 cm/sec. and its breadth is decreasing at the rate of 3 cm/sec. Find the rate of change of the area of the rectangle when length is 12 cm and breadth is 8 cm.
5. Find the equation of the tangent to the curve y = x² – 2x + 7 which is (1) Parallel to the line 2x − y + 9 = 0 (2) Perpendicular to the line 5y – 15x = 13.

###### Important Questions
• Find the equation of the normal at a point on the curve x² = 4y, which passes through the point (1, 2). Also find the equation of the corresponding tangent.
• Find the point on the curve 9y² = x³ where the normal to the curve makes equal intercepts with the axes.
• If the sum of length of hypotenuse and a side of a right angled triangle is given, show that area of triangle is maximum, when the angle between them is π/3.
• Show that the cone of the greatest volume which can be inscribed in a given sphere has an altitude equal to 2/3 of the diameter of the sphere.
• A wire of length 36 m is to be cut into two pieces. One of the pieces is to be made into a square and the other into a circle. What should be the length of the two pieces, so that the combined area of the square and the circle is minimum?