你可以證到PQ=MN and parallel
MPQN係平行四邊形
然後佢左右對稱
你再諗下左右對稱嘅平行四邊形代表啲咩
[DSE數學2018] Maths 討論區 (2)
dse杏林
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我覺得A1,2 35分鐘去到15年都仲得 呢兩年A2變深 B反而變淺
想問呢條最尾用sum to infinity計然後比較大細得唔得
我見佢答案係兩個相減計m係負數
咁唔係一樣意思咩得
想問呢條最尾用sum to infinity計然後比較大細得唔得
我見佢答案係兩個partial sum相減係負數
咁唔係一樣意思咩Thanks 想問埋有冇可能會淨係用一是但一種做 因為我見有年答案係partial sum 有年又sum to infinity
想問埋有冇可能會淨係用一是但一種做 因為我見有年答案係partial sum 有年又sum to infinity 咩係partial sum
好似唔得
就好似踢波咁
完場贏咗嗰隊都有可能中途落後過
就好似踢波咁
完場贏咗嗰隊都有可能中途落後過
要證埋個partial sum is monotonic increasing 
我都有諗過呢個原因都覺得好大機會係
所以想問題目有咩字眼會令我知道要用咩方法
定係咁樣比較就一定要兩個partial sum相減
所以想問題目有咩字眼會令我知道要用咩方法
定係咁樣比較就一定要兩個partial sum相減
呢個問法係咪應該諗成 要每一年總數都會大過另一個 所以要let個m嚟check
但我第一感會睇成 只要某一年總數大過另一個 句claim就啱
用返英文一般理解咪得囉
走去計較咩字眼就用咩方法好似有啲讀死書
走去計較咩字眼就用咩方法好似有啲讀死書
我知自己錯咩了 唔該晒樓上巴打
你考個陣啱咪得囉
There are 8 balls of different colours in a bag. 4 balls are randomly drawn from the bag one by one with replacement and their colours are recorded.
(a) Find the probability that the two balls drawn are of the same colour and another two balls drawn are of another same colour.
(b) Find the probability that the four balls drawn are of two colours only.
(a) Find the probability that the two balls drawn are of the same colour and another two balls drawn are of another same colour.
(b) Find the probability that the four balls drawn are of two colours only.
a.(1/8)^4*8c2*4c2
b.(1/8)^4*8c2*4c1+(a)
b.(1/8)^4*8c2*4c1+(a)
There are 8 balls of different colours in a bag. 4 balls are randomly drawn from the bag one by one with replacement and their colours are recorded.a.(1/8)^4*8c2*4c2
(a) Find the probability that the two balls drawn are of the same colour and another two balls drawn are of another same colour.
(b) Find the probability that the four balls drawn are of two colours only.
b.(1/8)^4*8c2*4c1*2+(a)