The number of different words (eight-letter words) ending and beg

Subject

Mathematics

Class

NDA Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

11.

If the graph of a quadratic polynomial lies entirely above x-axis, then which one of the following is correct ?

  • Both the roots are real

  • One root is real and the other is complex

  • Both the roots are complex

  • Cannot say


12.

The modulus and principal argument of the complex number 1 + 2i1 - 1 - i2 are respectively

  • 1, 0

  • 1, 1

  • 2, 0

  • 2, 1


13.

If z + 4  3, then maximum value of z +1 is

  • 0

  • 4

  • 6

  • 10


14.

The number of roots of the equation z2 = 2z is

  • 2

  • 3

  • 4

  • zero


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15.

If cotα and cotβ are the roots of the equation x2 + bx + c = 0 with b  0, then the value of cot(α + β) is

  • c - 1b

  • 1 - cb

  • bc - 1

  • b1 - c


16.

The sum of the roots of the equation x2 + bx + c = 0 (where b and c are non-zero) is equal to the sum of the  reciprocals of their squares. Then 1c, b, cb are in

  • AP

  • GP

  • HP

  • None of the above


17.

The sum of the roots of the equation ax2 + x + c = 0 (where a and c are non-zero) is equal to the sum of the reciprocals of their squares. Then a, ca2, c2 are in

  • AP

  • GP

  • HP

  • None of the above


18.

The value of C7, 0 + C7, 1 + C7, 1 + C7, 2 + ... + C7, 6 + C7, 7 is

  • 254

  • 255

  • 256

  • 257


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19.

The number of different words (eight-letter words) ending and beginning with a consonant which can bemade out of the letters of the word 'EQUATlON' is

  • 5200

  • 4320

  • 3000

  • 2160


B.

4320

3P2 × 6! = 6 × 720= 4320


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20.

The fifth term of an AP of 11 terms, whose sum is n2 - 2n, is

  • 5

  • 7

  • 8

  • 15


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