数学Paper 1讨论专区

peaceboy

I know..but how to differentitate which formula to use if they mention abt coefficient of x and anot ...
vick5821 发表于 26-7-2010 09:45 PM

    恩，一样的

vick5821

same meh?? T7 = nC6, but X^7 = nC7 wor..

vick5821

and add on to the ques, hence, find the smallest values of m and n which satisfy the above equation.

peaceboy

same meh?? T7 = nC6, but X^7 = nC7 wor..
vick5821 发表于 26-7-2010 11:46 PM

    因为X^7是第8个term

find the smallest values of m and n which satisfy the above equation.

4n - 7m - 3 =0
n = (3+7m)/4
since n>= m and n and m are +ve integer

by using trial and error ,
m=0, n=3/4 (rejected)
m=1 , n= 10/4 rejected
m=2 , n= 17/4 rejected
m=3 , n= 24/4 = 6
therefore , the smallest value that satisfy the equation is m=3 n=6
方法笨下，不过我也不会其他方法

vick5821

回复 1464# peaceboy

so X^(m+1) is which term?? T(m + 2 ) term??

peaceboy

回复  peaceboy

so X^(m+1) is which term?? T(m + 2 ) term??
vick5821 发表于 27-7-2010 12:43 AM

    没错

vick5821

回复 1466# peaceboy


    谢谢你的帮忙

yingchin

square root(x+2) - square root (x-6) = square root(x-3)

谢谢=）是不是要Square both sides, 然后 expand它？ 但是我不太会expand有square root 的 ToT

peaceboy

square root(x+2) - square root (x-6) = square root(x-3)

谢谢=）是不是要Square both sides, 然后 ex ...
yingchin 发表于 27-7-2010 06:07 PM

    对，这种情况还要square 2 次

(x+2)^(1/2) - (x-6)^(1/2) = (x-3)^(1/2)
square both side

x+2 + x - 6 - 2 [(x+2)(x-6)]^(1/2) = x-3
x-1 = 2[x^2 - 4x -12]^(1/2)
square both side again
x^2-2x+1 = 4[x^2-4x-12]
3x^2 -14x - 49 = 0
(3x+7)(x-7) =0
x=-7/3 , 7

然后sub回进去看有没有要rejected 的

lonely_world

麻烦教我一下

Lov瑜瑜4ever

麻烦教我一下
lonely_world 发表于 27-7-2010 09:07 PM

这是mathT的第几课啊？

whyyie

回复 1471# Lov瑜瑜4ever

Paper 1 最后一课 Integration

yingchin

回复 1469# peaceboy


   谢谢你

peaceboy

麻烦教我一下
lonely_world 发表于 27-7-2010 09:07 PM

integration by part...

拿e^(-x) = u , x^(-1/2) = dv/dx 就对了

之后trapezium rule ... sub formula 就没问题了吧

vick5821

Given A(1,4) and B (-5, 2). P divides AB externally in the ratio 3:1. Find the coordinate of P..I dun understand how to do divide externally ques..

peaceboy

Given A(1,4) and B (-5, 2). P divides AB externally in the ratio 3:1. Find the coordinate of P..I du ...
vick5821 发表于 3-8-2010 04:43 PM

    x__________2______x______1_____x
  A(1,4)                      B(-5, 2)             P(x,y)


divide externally 的意思就是放在线AB的线外面...
所以你看得出P和A的距离是3
P和B的距离是1......

[ 1(1) + 2 (x) ] /(1+2) = -5
x= -8

[ 1(4) + 2 (y) ] /(1+2)  = 2
y=1

P = (-8,1)

教到自己都心虚......呵呵...

vick5821

P divide Ab in the ratio of m:n mean PA =m, PB =n? no mater divide internally or externally??

peaceboy

P divide Ab in the ratio of m:n mean PA =m, PB =n? no mater divide internally or externally??
vick5821 发表于 3-8-2010 06:39 PM

    是呱......

Lov瑜瑜4ever

这不是SPM就有教了吗？？

vick5821

divides externally new things ma..If got ratio like -2:3 how ar???