|
|
发表于 29-8-2010 01:34 PM
|
显示全部楼层
|
Prove that the straight line x-ty+4t^2 = 0 touches the parabola y^2 = 16x for all values of t and find the point of contact. |
|
|
|
|
|
|
|
|
|
|
|
发表于 29-8-2010 02:11 PM
|
显示全部楼层
Prove that the straight line x-ty+4t^2 = 0 touches the parabola y^2 = 16x for all values of t and fi ...
whyyie 发表于 29-8-2010 01:34 PM 
 |
|
|
|
|
|
|
|
|
|
|
|
发表于 29-8-2010 02:14 PM
|
显示全部楼层
回复 Allmaths
你是在什么时候剃法为憎？？
芭樂 发表于 29-8-2010 12:15 PM
自从你这么说后... |
|
|
|
|
|
|
|
|
|
|
|
发表于 30-8-2010 12:43 PM
|
显示全部楼层
|
Uhmm how to determine the convergence or divergence of a series? |
|
|
|
|
|
|
|
|
|
|
|
发表于 30-8-2010 10:30 PM
|
显示全部楼层
|
in order to determine,u need to identify first whether the series is AP or GP. If it is an AP , then no convergence or divergence.If it is a GP , then u need to find the common ratio. If the magnitude of the common ratio is less than 1, then is convergence. If common ratio is bigger than 1, then is divergence |
|
|
|
|
|
|
|
|
|
|
|
发表于 30-8-2010 11:15 PM
|
显示全部楼层
第一part 我做到 4surd(3/2) .... |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 07:46 AM
|
显示全部楼层
1. Find the value of a and b such that the non-zero term in the expansion of
1+ax/1+bx-e^x
in ascending power of x is the term in x^3. |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 09:20 AM
|
显示全部楼层
回复 1607# blazex
(1+ax/1+bx) -e^x= (1+ ax)(1+bx)^-1 - e^x
然后用expansion的formula. formula book里面有 |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 09:44 AM
|
显示全部楼层
第一part 我做到 4surd(3/2) ....
whyyie 发表于 30-8-2010 11:15 PM
如果y^2=4-x 和 y^2=x+1 的话就可以prove到 (20/3)(5/2)^(1/2)... |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 10:12 AM
|
显示全部楼层
回复 1609# Allmaths
还是算不到.... |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 10:17 AM
|
显示全部楼层
1. Find the value of a and b such that the non-zero term in the expansion of
1+ax/1+bx ...
blazex 发表于 31-8-2010 07:46 AM
这题应该是 1+ax/1+bx=e^x...因为没有'='..你没有equation可以拿来compare...
再说这题需要知道e^x的expansion...e^x的expansion是在FMT里才有学...是maclaurin's series...
注:e^x=1+x+(x^2)/2!+(x^3)/3!+...+(x^n)/n! (for all x) |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 10:28 AM
|
显示全部楼层
回复 Allmaths
还是算不到....
whyyie 发表于 31-8-2010 10:12 AM
 |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 11:02 AM
|
显示全部楼层
回复 1612# Allmaths
怎样看是(4-y^2) - (y^2-1)还是 (y^2-1)-(4-y^2)? [不以modulus为前提] |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 11:23 AM
|
显示全部楼层
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 11:55 AM
|
显示全部楼层
show that the centre of the circles passing through the point (3,2) and (6,3) r located on the line 3x+y=16.2 of the circle touch x+2y=2.Find the equation of these circle.
ans x-5)^2+(y-1)^2 =5
(x-1)^2+(y-13)^2=125 |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 12:41 PM
|
显示全部楼层
回复 1605# 數學神童
ooo okie thx  |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 01:18 PM
|
显示全部楼层
回复 1614# Allmaths
差别知识(-)sign 罢了... 不用modulus怎样决定? |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 01:19 PM
|
显示全部楼层
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 04:48 PM
|
显示全部楼层
回复 Allmaths
怎样看是(4-y^2) - (y^2-1)还是 (y^2-1)-(4-y^2)? [不以modulus为前提]
whyyie 发表于 31-8-2010 11:02 AM 
从graph 可以看出，大的area减掉小的... |
|
|
|
|
|
|
|
|
|
|
|
发表于 31-8-2010 04:52 PM
|
显示全部楼层
whyyie 发表于 31-8-2010 01:19 PM
应该没问题吧，第一个部分算了用计算机double check
第二个部分通常是(A+2I)P = P 或者(A+2I)P=I之类的,所以(A+2I)^15P 大概也等于P 或 A+2I 之类的 = =
懒惰算，不好意思 |
|
|
|
|
|
|
|
|
|
| |
 本周最热论坛帖子
|
998 
53
