CBSE Guess > Papers > Important Questions > Class XI > 2012 > Mathematics > Mathematics By Mr. Chetan Jain

CBSE CLASS XI

Using principle of mathematical induction prove that:

1. 
2. has 7 in unit place for all natural number
3. 
4. is divisible by 3 for all natural numbers.
5. n + n² is an even number for all natural numbers.

Chapter – 5


6. Find real values of x and y for which the complex numbers (- 3 + ix²y) and( x² + y +4i) are complex conjugate of each other.



7. If z₁ and z₂ are complex numbers such that

Ans: 3

8. Show that a real value of x will satisfy the equation:
9. Find the square root of 7 – 24i.
10. Express sin 30⁰ + i cos 30⁰ in polar form

    Chapter - 6

11. An electrician can be paid under two schemes as given below:

    Scheme I : Rs. 500 and Rs. 70 per hour

    scheme II : Rs. 120 per hour.

    If the work takes x hours to complete, for what value of x does the scheme I give the electrician better wages?

12. Solve the inequality



13. Solve the inequality



14. The cost and revenue functions of a product are given by C(x) = 2x + 400 and R(x) = 6x + 20 respectively, where
    “x” is the number of items produced by the manufacturer. How many items atleast the manufacturer must sell to realize a profit.

    Ans : 95

15. Exhibit the solution of linear inequation graphically:

    Chapter – 7

16. How many different numbers of 6 – digits can be formed by using the digits 1, 2, 1, 2, 0, 2?

    Ans : 50

17. Find the number of (i) Combinations (ii) Permutations of 4 letters taken from the word EXAMINATION.

    Ans: (i) 136 (ii) 2454

18. There are 15 points in a plane, no 3 of them are in a straight line except 4 which are collinear. Find the number of

    (i) straight lines

    (ii) triangle formed by joining them.

    Ans : (i) 100 (ii) 451

19. Find the number of rectangles in the adjoining figure:

    Ans:60

20. There 6 questions in a question paper. In how many ways can a student solve one or more questions: Ans: 63

Submitted By Mr. Chetan Jain
About author: PGT Maths, Kv Deoli
Email: [email protected]