引用第0樓朗仔於2010-03-31 21:44發表的“CE MATHS”: let F( x ) be a polynomial. If F (x ) is disvisble by x-1 , WHich IS THE FACTOR OF F(2X+1) [表情] A.X B.X-3 C.2X-1 .......
you may consider another method since F (x ) is disvisble by x-1
so....we know F(x)= (x-1)Q(x)
將2x+1代入去x
F(2x+1) = (2x+1-1)Q(2x+1) =2x Q(2x+1)
obviously x is the factor of F(2X+1)
朗仔
2010-04-01 01:27
引用第17樓反傳統於2010-04-01 01:24發表的“”: you may consider another method since F (x ) is disvisble by x-1 .......
好勁
plmplm
2010-04-01 01:27
而家CE MATHS 咁深既.. 我讀完AL都吾識TIM
你班友cher夠未
2010-04-01 02:28
sosad呢題琴晚先問完j3
ab34
2010-04-01 04:45
差d唔識計.... a maths 個d數記得點計，但係maths d野唔係好記得
朗仔
2010-04-01 17:51
ax^2+2bx+c=0 has two equal real roots, which of the following is/ara true?
I. both roots are -b/a II. a,b,c form a geometric progression III. a,b,c form an arithmetic progresion
ans: I AND II
朗仔
2010-04-01 18:58
if a not equal to +-1, then 1+a^2+a^4+.....+ a^2n = ????
引用第22樓朗仔於2010-04-01 17:51發表的“”: ax^2+2bx+c=0 has two real roots, which of the following is/ara true? I. both roots are -b/a II. a,b,c form a geometric progression III. a,b,c form an arithmetic progresion .......
你有冇打錯野? 好似有d矛盾
rBB
2010-04-01 20:52
引用第23樓朗仔於2010-04-01 18:58發表的“”: if a not equal to +-1, then 1+a^2+a^4+.....+ a^2n = ???? ans: 1-a^(2n+2) / 1-a^2
this is a GS the first term = 1 common ratio = a^2 no. of terms = n+1
sum = [1-(common ratio)^no. of terms]/(1-common ratio) = [1-a^2^n+1]/1-a^2 =(1-a^2n+2) / 1-a^2
OldSosad
2010-04-01 20:54
引用第26樓rBB於2010-04-01 20:52發表的“”: this is a GS the first term = 1 common ratio = a^2 no. of terms = n+1 .......
no. of terms = n+1
咦,呢個點解既?
rBB
2010-04-01 20:56
引用第27樓OldSosad於2010-04-01 20:54發表的“”: no. of terms = n+1 咦,呢個點解既? [表情]
SUB number: 1+a^2+a^4+.....+ a^2n =
when n=1 : 1+a^2 ======>2 terms when n=3 : 1+a^2+a^4+a^6 =======> 4 terms
OldSosad
2010-04-01 21:00
引用第28樓rBB於2010-04-01 20:56發表的“”: SUB number: 1+a^2+a^4+.....+ a^2n = when n=1 : 1+a^2 ======>2 terms .......
引用第22樓朗仔於2010-04-01 17:51發表的“”: ax^2+2bx+c=0 has two equal real roots, which of the following is/ara true? I. both roots are -b/a II. a,b,c form a geometric progression III. a,b,c form an arithmetic progresion .......
delta = 0 4b^2 - 4ac = 0 b^2 -ac = 0 b^2 = ac
by definition, II is correct
delta =0 roots = -2b\2a = -b/a
OldSosad
2010-04-04 16:36
我想問兩條 ..
6 men can finish a piece of work in 10days . If y more men are added, the work can be done in 4days. Find y. A. 8 B. 9 C. 10 D.11
答案 : B
Which of the following is a factor of 2(a-b)^2 - a^2 + b^2 ? A. a-3b B. a-2b C. a+b D. a+3b
答案 : A
唔知點做呢?
丹尼屎
2010-04-04 17:05
引用第38樓OldSosad於2010-04-04 16:36發表的“”: 我想問兩條 .. 6 men can finish a piece of work in 10days . If y more men are added, the work can be done in 4days. Find y. A. 8 B. 9 C. 10 D.11 .......
6 個人用左 10 日 : 6x10
(6+y) 個人用左 4 日 : (6+y)x4
.'. 60 = 24 + 4y y = 9
Grape
2010-04-04 17:06
6 men can finish a piece of work in 10days . If y more men are added, the work can be done in 4days. Find y.
6 men can finish a piece of work in 10days 1 men can finish 1/60 of work everyday
60/4 = 15
15-6=9
Grape
2010-04-04 17:07
Which of the following is a factor of 2(a-b)^2 - a^2 + b^2 ?
引用第38樓OldSosad於2010-04-04 16:36發表的“”: 我想問兩條 .. 6 men can finish a piece of work in 10days . If y more men are added, the work can be done in 4days. Find y. A. 8 B. 9 C. 10 D.11 .......
