NCERT Solutions

Class –VIII Mathematics (Ex. 3.4) NCERT SOLUTION 1. State whether true or false: (a) All rectangles are squares. (b) All rhombuses are parallelograms. (c) All squares are rhombuses and also rectangles. (d) All squares are not parallelograms. (e) All kites are rhombuses. (f) All rhombuses are kites. (g) All parallelograms are trapeziums. (h) All squares … Read more

Miscellaneous Exercise 1. Three vertices of a parallelogram ABCD are A B and C Find the coordinates of the fourth vertex. Ans. Let D be the fourth vertex of parallelogram ABCD. Since, the diagonals of a parallelogram bisect each other. Therefore, the mid-point of AAAC and BD coincide. Coordinates of mid-point of AC = = … Read more

Exercise 16.3 1. Which of the following cannot be valid assignment of probabilities for outcomes of sample space S = Assignment (a) 0.1 0.01 0.05 0.03 0.01 0.2 0.6 (b) (c) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 (d) –0.1 0.2 0.3 0.4 –0.2 0.1 0.3 (e) Ans. (a) Here probability of each outcome is … Read more

Redox Reactions  1. Assign oxidation numbers to the underlined elements in each of the following species: (a) (b) (c) (d) (e) (f) (g) (h) 2. What are the oxidation numbers of the underlined elements in each of the following and how do you rationalise your results? (a) 3. Justify that the following reactions are redox … Read more

Miscellaneous Exercise 1. Find the derivative of following functions from first principle: (i) (ii) (iii) (iv) Ans. (i)Given: then = = = (ii)Given: then = = = (iii)Given: then = = = (iv)Given: then = = = Find the derivative of the following functions (it is to be understood that and are fixed non-zero constants … Read more

Miscellaneous Exercise 1. A box contains 10 red marbles, 20 blue marbles and 30 green marbles. 5 marbles are drawn from the box, what is the probability that: (i) all will be blue? (ii) at least one will be green? Ans. Total marks = 10 + 20 + 30 = 60 We have to draw … Read more

Exercise 13.1 Evaluate the following limits in Exercises 1 to 22. 1. Ans. 3 + 3 = 6 2. Ans. 3. Ans. 4. Ans. 5. Ans. 6. Ans. Putting as 7. Ans. = = 8. Ans. = = = 9. Ans. 10. Ans. = = = = = 1 + 1 = 2 11. Ans. … Read more

Exercise 13.2 1. Find the derivative of at Ans. Here Therefore, Derivative of at is 2. Find the derivative of at Ans. Here Therefore, Derivative of at is 99 3. Find the derivative of at Ans. Here Therefore, Derivative of at is 1 4. Find the derivatives of the following functions from first principle: (i) … Read more