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发表于 25-5-2009 10:33 PM
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是咩？？？那不好意思拉 paiseh啦。。。对不起啦 |
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发表于 25-5-2009 10:57 PM
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回复 41# phoebie 的帖子
不用紧！
还没人回复的！～～ |
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发表于 26-5-2009 12:14 AM
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发表于 26-5-2009 12:40 AM
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发表于 26-5-2009 12:44 AM
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你忘了你的a是等于square root of x plus 1/ square root of x的吗？？？
如果square root of x + 1/ square root of x = 0
最后x还是等于 -1
我不懂对不对啊 |
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发表于 26-5-2009 12:48 AM
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ermmmmm
对了
我想问下
这题到底是paper2还是paper1?????? |
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发表于 26-5-2009 12:51 AM
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原帖由 phoebie 于 26-5-2009 12:44 AM 发表 
你忘了你的a是等于square root of x plus 1/ square root of x的吗？？？
如果square root of x + 1/ square root of x = 0
最后x还是等于 -1
我不懂对不对啊
答案不可能是 -1的原因是因为根号（square root）里面的数字不可以是negative的。 |
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发表于 26-5-2009 12:51 AM
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发表于 26-5-2009 07:26 PM
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1-solve the equation x^(1/2)+x^(-1/2)=2( x^(1/2)-x^(-1/2)).
对不起，大家！我把 — 写成+！
找到了，整个equation要乘于square rootsX!
[ 本帖最后由 ★平常★ 于 26-5-2009 07:30 PM 编辑 ] |
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发表于 26-5-2009 08:39 PM
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原帖由 ★平常★ 于 26-5-2009 07:26 PM 发表 
1-solve the equation x^(1/2)+x^(-1/2)=2( x^(1/2)-x^(-1/2)).
对不起，大家！我把 — 写成+！
找到了，整个equation要乘于square rootsX!
酱的话我的方法对了 |
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发表于 26-5-2009 08:41 PM
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发表于 26-5-2009 08:50 PM
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帮我解下这几题！
3+2log(p+q)(1over p²- q²
6(2^(x-1))=10^(x-1)
5^(x+1)(2^(x+2))=3^(x+3) |
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发表于 26-5-2009 09:14 PM
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发表于 15-6-2009 09:16 PM
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原帖由 phoebie 于 26-5-2009 08:39 PM 发表 
酱的话我的方法对了
我的做法这样可以吗？o.O
x^1/2+x^-1/2=2(x^1/2-x^-1/2)
let x^1/2=y
y+1/y=2y-2/y
3/y=y
y^2=3
(x^1/2)^2=3
x=3 |
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发表于 23-6-2009 10:20 PM
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请问你们的ｄｅｄｕｃｔｉｖｅ ｇｅｏｍｅｔｒｉｃ都是用背的吗?
还是有其他的方法 |
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发表于 23-6-2009 11:04 PM
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回复 55# 灰空 的帖子
一直做咯～不然不会做～
用背没效的～题目太多变化了～ |
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发表于 29-6-2009 05:37 PM
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大家好！
Three dice are thrown in a game. If 1 or 6 shows up, you will be paid 1p.
If neither 1 nor 6 show up, you will pay 5p.
i)How much gain or less is expected in 9 games?
ii)You are given opportunity to change the rule of the game if 1 or 6 appears. To make the game worthwhile, what is the minimum amount in everyday currency you would suggest for both payment?
Solved.
[ 本帖最后由 darksider 于 30-6-2009 02:50 PM 编辑 ] |
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发表于 9-7-2009 09:03 PM
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how to prove this one?
sin²Acos²B - cos²Asin²B = sin²A - sin²B
这题怎样做?
有人会吗? |
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发表于 10-7-2009 02:47 PM
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回复 58# lonely_world 的帖子
RHS: sin²A - sin²B= (sin²A - sin²B)(sin²A+cos²A)
=(sinA)^4+sin²A cos²A-sin²Asin²B-cos²Asin²B
=sin²A(sin²A+cos²A-sin²B)-cos²Asin²B
=sin²A(1-sin²B)-cos²Asin²B
=sin²Acos²B - cos²Asin²B LHS |
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发表于 11-7-2009 09:21 PM
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Chapter 2 Polynomials
请高手们帮我solve..谢谢！
Oxford fajar textbook pg 85
16. Show tat x+2 is a factor of the polynomial 2x³+x²-8x-4. Hence, find all the real roots of the equation 2x^6+x^4-8x² +4=0. Determine the set of values of x such tat 2x³+x²-8x-4<4-2x. (ans: +/- square root 2 ； x<2）
19. The roots of the quadratic equation ax² +bx+c=0 are α and Β .Show tat α + Β = -b/a and αΒ= c/a. If Β= 3α, show tat 3b²=16ac. Show tat the qadratic equation whose roots are α/Β² and Β/α² is ac²x² + (b³ -3abc)x + a²c=0.
20. Show tat -1/2 is a zero of the polynomial p(x)= 2x³-9x²+7x+6. If α and Β are the zeroes of q(x) where p(x) =(2x+1)q(x), show tat α and Β are real and find the values of α+Β and αΒ. Find a quadratic equation whose roots are α² and Β². Hence, find a cubic equation whose roots are 1/2, α² and Β².
(ans: α+Β=5 and αΒ=6, x²-13x+36=0, 2x³-27x²+85x-36=0)
21. Show tat the equation (α+3)x² + (6-2α)x + α-1=0 has real roots if α≤ 3/2. Find the values of α if one root is six times the other.(ans: -11, 33/25, -3)
有补习的朋友你们有notes 和额外的课外题吗？ |
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