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  • Question
  • If a + 1/a = ? 3, then the value of a6 - 1/a6 + 2 will be


  • Options
  • A. 3?3
  • B. 5
  • C. 1
  • D. 2

  • Correct Answer


  • Explanation

    Given equation is,
    a + 1/a = ?3 .............................(i)
    On squaring both sides
    ? a2 + 1/a2 + 2 = 3
    ? a2 + 1/a2 = 1 ..............................(ii)

    Now, multiplying Equation (i) and (ii), we get
    (a + 1/a) (a2 + 1/a2) = ?3
    ? a3 + a/a2 + a2/a + 1/a3 = ?3
    ? a3 + 1/a3 + ( a + 1/a ) = ?3
    now put the value of a + 1/a in above equation,
    ? a3 + 1/a3 + ?3 = ?3 [from Eq. (i)]
    ? a3 + 1/a3 = 0
    ? ( a6 + 1 ) /a3 = 0
    ? a6 + 1 = 0 x a3
    ? a6 + 1 = 0
    ? a6 = -1
    ? a6 - 1/a6 + 2
    put the value of a6
    = (-1)6 - 1/(-1)6 + 2
    = 1 - 1 + 2 = 2


  • More questions

    • 1. 
      The value of 47 / 10000 is?

    • Options
    • A. .0047
    • B. .0470
    • C. .00047
    • D. .000047
    • Discuss
    • 2. If 4x = 18y, then the value of ( x/y - 1) is

    • Options
    • A. 1 3
    • B. 7 2
    • C. 2 3
    • D. 3 2
    • Discuss
    • 3. 
      If the price of 23 toys is Rs. 276, then what will the price (Rs.) of 12 toys?

    • Options
    • A. 144
    • B. 158
    • C. 159
    • D. 166
    • Discuss
    • 4. 
      .02 =(......?.....)%

    • Options
    • A. 20
    • B. 2
    • C. .02
    • D. .2
    • Discuss
    • 5. 
      If 36 men can do a piece of work in 25 hours, in how many hours will 15 men do it?

    • Options
    • A. 45
    • B. 55
    • C. 60
    • D. 72
    • Discuss
    • 6. 
      2?63 / 11 =233

    • Options
    • A. 4
    • B. 3
    • C. 6
    • D. 5
    • Discuss
    • 7. 
      When 121012 is divided by 12, the remainder is

    • Options
    • A. 0
    • B. 2
    • C. 3
    • D. 4
    • Discuss
    • 8. 
      Aarti can do a piece of work in 6 days. In how many days will she complete three time of work of same type?

    • Options
    • A. 18 days
    • B. 21 days
    • C. 3 days
    • D. 6 days
    • Discuss
    • 9. 
      750.0003 ÷ 19.999 =?

    • Options
    • A. 49
    • B. 18
    • C. 22
    • D. 38
    • Discuss
    • 10. 
      105, 85, 60, 30, 0, - 45, - 90?

    • Options
    • A. 0
    • B. 85
    • C. -45
    • D. 60
    • Discuss


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