promotion image of download ymail app
Promoted
Qing asked in 科學及數學數學 · 7 years ago

maths 6條MOCK MC

Update:

不明34,35

34:不明為何let 2012^2012=10^n,是否計這類數如:2012^50也是let=10^n,5^2012也let=10^n?

至於35:不明這兩句點解:

5C2 ways for choosing 2 horizontal lines.

5C2 ways for choosing 2 vertical lines.

謝謝解答。

2 Answers

Rating
  • 7 years ago
    Favorite Answer

    14)

    (-k)³ + k(-k)² + 2k(-k) + 3 = k

    2k(-k) + 3 = k

    2k² + k - 3 = 0

    (2k + 3)(k - 1) = 0

    k = - 3/2 or k = 1

    (C)

    28)

    If f(x) and g(x) intersect at more than 1 point , then

    x² + ax + 1 = x² + bx + 1

    (a - b)x = 0 more than 1 root , if and only if a - b = 0 so a = b.

    P(a = b) = 6/6 * 1/6 = 1/6.

    (B)

    29)

    Note that 9² + 40² = 41² therefore it is a right-angled △.

    So K + G + 9*40/2 = E

    K + G + 180 = E

    (B)

    42)

    P(Koopa is ahead of Mario)

    = P(Koopa is the 1st)

    + P(Koopa is the 2nd and ahead of Mario)

    + P(Koopa is the 3rd and ahead of Mario)

    + P(Koopa is the last and ahead of Mario)

    = 1/4 + (1/4)(2/3) + (1/4)(1/3) + 0

    = 1/2

    (C)

    34)

    2012²º¹² = 10ⁿ

    2012log2012 = n

    6646.899488 = n

    So 2012²º¹² have 6647 digits.

    (C)

    44)

    5C2 ways for choosing 2 horizontal lines.

    5C2 ways for choosing 2 vertical lines.

    There are 5C2 * 5C2 = 100 rectangles can be choosed.

    (D)

    2013-03-03 20:48:16 補充:

    34)

    2012²º¹²

    = 10^6646.899488

    所以

    10^6646 = 100...00(6646個0) < 2012²º¹² < 10^6647 = 100...00(6647個0)

    肯定 2012²º¹² 是 6647 位數。

    44)

    4 x 4 正方由 5 橫 5 直所組成 ,

    一矩形被唯一的某2橫及某2直所確定,反之亦然。

    2013-03-03 20:50:42 補充:

    5C2 即 5 條抽 2 條的方法數量 , 即 5 * 4 / 2 = 10。

    • Commenter avatarLogin to reply the answers
  • 7 years ago
    • Commenter avatarLogin to reply the answers
Still have questions? Get your answers by asking now.