Surds and Indices


  1. If m = 7 - 4√3, then (√m + 1/√m) = ?











  1. View Hint View Answer Discuss in Forum

    Given that ,
    m = 7 - 4√3
    Then I/m = 1/7 - 4√3......................(1)

    Now multiply and divide with 7 + 4√3 in Eq. (1)
    We will get,
    1/m = ( 1/7 - 4√3 ) x ( 7 + 4√3 / 7 + 4√3)
    1/m = ( 7 + 4√3 )/ ( 7 - 4√3 ) x ( 7 + 4√3

    Correct Option: C

    Given that ,
    m = 7 - 4√3
    Then I/m = 1/7 - 4√3......................(1)

    Now multiply and divide with 7 + 4√3 in Eq. (1)
    We will get,
    1/m = ( 1/7 - 4√3 ) x ( 7 + 4√3 / 7 + 4√3)
    1/m = ( 7 + 4√3 )/ ( 7 - 4√3 ) x ( 7 + 4√3
    1/m = ( 7 + 4√3 ) / ( 72 - ( 4√3)2 )
    1/m = ( 7 + 4√3 ) / ( 49 - 4 x 4 x 3 )
    1/m = ( 7 + 4√3 ) /49 - 48
    1/m = ( 7 + 4√3 ) / 1
    1/m = 7 + 4√3
    m + 1/m = 14
    ⇒ ( m + 1/m ) + 2 = 14 + 2 = 16
    ∴ (√m + 1/√m)2 = ( m + 1/m )+ 2
    ⇒ (√m + 1/√m)2 = 16
    ⇒ (√m + 1/√m)2 = 42
    ⇒ (√m + 1/√m) = 4


  1. (100)0 is equivalent to :









  1. View Hint View Answer Discuss in Forum

    If any given number (suppose x) is a rational number other than zero, then x0 = 1.

    Correct Option: C

    If any given number (suppose x) is a rational number other than zero, then x0 = 1.



  1. If √2n = 64 , what will be the value of n?









  1. View Hint View Answer Discuss in Forum

    2n = 64 ⇒ 2n = (64)2
    ⇒ 2n = (2 × 2 × 2 × 2 × 2 × 2)2
    ⇒ 2n = (26)2 ⇒ 2n

    Correct Option: C

    2n = 64 ⇒ 2n = (64)2
    ⇒ 2n = (2 × 2 × 2 × 2 × 2 × 2)2
    ⇒ 2n = (26)2 ⇒ 2n = 26 × 2 = 212
    ⇒ n = 12.


  1. The value of 6a3 b3 c2 ÷ 2ab2 c is :









  1. View Hint View Answer Discuss in Forum

    6a3 b3 c2 ÷ 2ab2c

    =
    6a3b3c2
    2ab2c

    Correct Option: B

    6a3 b3 c2 ÷ 2ab2c

    =
    6a3b3c2
    2ab2c

    = 3a3 - 1 b3 - 2 c2 - 1 = 3a2bc



  1. If m and n are natural numbers, the m√n









  1. View Hint View Answer Discuss in Forum

    If m and n are natural numbers, then m√n is irrational unless n is mth power of an integer.

    Correct Option: B

    If m and n are natural numbers, then m√n is irrational unless n is mth power of an integer.