Pure 03/I/Q12

kawai

Originally posted by Sol_Campbell at 2005-3-18 09:09 PM:

所以咪話少野背,唔係冇野背囉

arc length果d 公式我仲未記到

我又唔覺得少喎

久違

Originally posted by Sol_Campbell at 2005-3-18 09:09 PM:

所以咪話少野背,唔係冇野背囉

arc length果d 公式我仲未記到

practice makes perfect

久違

Originally posted by kawai at 2005-3-18 09:13 PM:

我又唔覺得少喎

積分好多

久違

Originally posted by Raul at 2005-3-18 09:07 PM:

好過bio啦

chem

Raul

Originally posted by 久違 at 2005-3-18 21:14:

chem

192樣

kawai

Originally posted by 久違 at 2005-3-18 09:14 PM:

chem

都係inorg同org chem姐

2076

Originally posted by 久違 at 2005-3-18 08:59 PM:

不段做pape
唔識都變識

雖然past paper d solution睇得明
但返去做書o個D, 完全做唔到, 又冇solution係手
今日a.math section a題locus空晒, 題LQ避左,
做左trigo 3d, 又係唔識

問數實際D.

有個圓x^2+y^2=1, 有一點variable pt P在圓外, M&N都在圓上
令PM同PN成為兩條tangent, 角MPN=90度
(a)part show PMON is square做到
(b)part find locus of P 就完全唔知點做

識既可否賜教, 我only想知做數個方向, 唔使答案

Sol_Campbell

Originally posted by 2076 at 2005-3-19 12:09 AM:


雖然past paper d solution睇得明
但返去做書o個D, 完全做唔到, 又冇solution係手
今日a.math section a題locus空晒, 題LQ避左,
做左trigo 3d, 又係唔識

問數實際D.

識既可否賜教, 我only ...

你可以試下畫圖,睇下條locus係點再做會易d

因為係正方形,PO長度係root2
O (0,0)
let P(x,y)
(x-0)^2+(y-0)^2=2
x^2+y^2=2
應該係咁

如果真係岩既話,我覺得呢類好似唔多見,
通常係x=一堆野,y又等於一堆野(好似話P係兩點既mid pt)
之後代下代下就搵到x,y既關係....唔識講
一係你俾多條ex黎丫

[ Last edited by Sol_Campbell on 19-3-2005 at 01:00 AM ]

久違

Originally posted by Sol_Campbell at 2005-3-19 12:54 AM:
你可以試下畫圖,睇下條locus係點再做會易d

因為係正方形,PO長度係root2
O (0,0)
let P(x,y)
(x-0)^2+(y-0)^2=2
x^2+y^2=2
應該係咁

如果真係岩既話,我覺得呢類好似唔多見,
通常係x=一堆野 ...

搵x,y既關係就得嫁啦

久違

Originally posted by Sol_Campbell at 2005-3-19 12:54 AM:
你可以試下畫圖,睇下條locus係點再做會易d

因為係正方形,PO長度係root2
O (0,0)
let P(x,y)
(x-0)^2+(y-0)^2=2
x^2+y^2=2
應該係咁

如果真係岩既話,我覺得呢類好似唔多見,
通常係x=一堆野 ...

mo
應該岩...唔洗驚

[ Last edited by 久違 on 19-3-2005 at 02:27 AM ]

2076

Originally posted by Sol_Campbell at 2005-3-19 12:54 AM:
你可以試下畫圖,睇下條locus係點再做會易d

因為係正方形,PO長度係root2
O (0,0)
let P(x,y)
(x-0)^2+(y-0)^2=2
x^2+y^2=2
應該係咁

如果真係岩既話,我覺得呢類好似唔多見,
通常係x=一堆野,y又等於一堆野(好似話P係兩點既mid pt)
之後代下代下就搵到x,y既關係....唔識講
一係你俾多條ex黎丫

原來係咁, 我個同學都一樣案, 唔該晒.
我靜係識做x同y in terms of t,
跟住find mid-pt or 畀個比例o個種

睇來可能真係要出去補補圓形,locus,同co-geo了

beckham312oo

Originally posted by Sol_Campbell at 2005-3-18 09:09 PM:

所以咪話少野背,唔係冇野背囉

arc length果d 公式我仲未記到

arc length 唔好背啦...推出黎好好多

prove:assume 每一小段arc length為一個個直角三角形
then
integrate ds=integrate root(dx^2+dy^2)(pyth.thm)
         抽dx=>s=integrate root(1+dy/dx^2)dx
         抽dy=>s=integrate root(1+dx/dy^2)dy
         抽dt=>s=integrate root(dx/dt^2+dy/dt^2)dt



睇番原來我漏左integral sign
同埋要加番upper limit& lower limit

[ Last edited by beckham312oo on 20-3-2005 at 05:11 PM ]

麥旋風

Originally posted by beckham312oo at 2005-3-19 10:03 AM:
arc length 唔好背啦...推出黎好好多

prove:assume 每一小段arc length為一個個直角三角形
then s=root(dx^2+dy^2)(pyth.thm)
         抽dx=>s=root(1+dy/dx^2)dx
         抽dy=>s=root(1+dx/dy^2 ...

有得推就唔同D
不過Pure D時間好緊密
推唔推得切都成問題

所以我like Physics多D
好多野好生活法
容易D搵方法去記
而且時間冇咁緊迫

beckham312oo

Originally posted by 麥旋風 at 2005-3-20 01:47 PM:

有得推就唔同D
不過Pure D時間好緊密
推唔推得切都成問題

所以我like Physics多D
好多野好生活法
容易D搵方法去記
而且時間冇咁緊迫

不過phy 好多都係推出黎啦...
唔通真係會走去記 Y=Fl/Ax & k=YA/l o個d式咩
不過又真係好推過pure 好多既

kawai

Originally posted by beckham312oo at 2005-3-20 05:11 PM:
不過phy 好多都係推出黎啦...
唔通真係會走去記 Y=Fl/Ax & k=YA/l o個d式咩
不過又真係好推過pure 好多既

後面有嫁嘛

kawai

Originally posted by 麥旋風 at 2005-3-20 01:47 PM:

有得推就唔同D
不過Pure D時間好緊密
推唔推得切都成問題

所以我like Physics多D
好多野好生活法
容易D搵方法去記
而且時間冇咁緊迫

我覺得phy好似有乜野記咋喎
essay除外

麥旋風

Originally posted by kawai at 2005-3-20 05:18 PM:

我覺得phy好似有乜野記咋喎
essay除外

頂，唔計essay想點

不過其實都有野記既
唔可以單靠睇後面
否則有多野唔識變通

kawai

Originally posted by 麥旋風 at 2005-3-20 06:27 PM:

頂，唔計essay想點

不過其實都有野記既
唔可以單靠睇後面
否則有多野唔識變通

當然唔係完全冇啦
thin film同extra structure d式就冇比

天生射手

Originally posted by 2076 at 2005-3-18 04:35 PM:
各位師兄: 其實Pure Maths難唔難讀架?

我依家中五, A Math成績一般, 有幾課仲好弱
例如見到"Locus"就例牌一片空白,
如果到中六, 讀Pure會唔會更加辛苦??

讀就Add. Maths易
考就Pure Maths易

CYBASTER

Originally posted by 天生射手 at 2005-3-22 12:49 PM:


讀就Add. Maths易
考就Pure Maths易

pure math d pastpaper真係...