« previous next »
Pages: 1 [2] 3 4 ... 7   Go Down

Author Topic: IGCSE Maths doubt(paper 4)  (Read 14372 times)

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
Re: IGCSE Maths doubt(paper 4)
« Reply #15 on: October 31, 2009, 07:09:00 am »
Quote from: ~Alpha on October 31, 2009, 07:04:00 am

Simplified, isn't it x > 2 ???

non..ofcourse not..it is <=4 rite..
Logged
divine intervention!

Offline ~~~~shreyapril~~~~

  • SF Master
  • ******
  • Posts: 2606
  • Reputation: 2640
  • Gender: Male
  • "Prototype"
Re: IGCSE Maths doubt(paper 4)
« Reply #16 on: October 31, 2009, 08:15:38 am »
i think sameer's ans is rite??

dude try picking up ur phone!!


calling from 1 hr!!
Logged
Friendship is like peeing on yourself. Everyone can see it but only you get the warm feeling that it gives :D :P :)

Alpha

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #17 on: October 31, 2009, 10:33:57 am »
Quote from: A@di on October 31, 2009, 07:09:00 am
non..ofcourse not..it is <=4 rite..



x is greater or equal to 4... See well.
Logged

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
Re: IGCSE Maths doubt(paper 4)
« Reply #18 on: October 31, 2009, 11:02:01 am »
Quote from: ~Alpha on October 31, 2009, 10:33:57 am


x is greater or equal to 4... See well.

u see well...its x is less than or equal to 4
Logged
divine intervention!

Offline ~~~~shreyapril~~~~

  • SF Master
  • ******
  • Posts: 2606
  • Reputation: 2640
  • Gender: Male
  • "Prototype"
Re: IGCSE Maths doubt(paper 4)
« Reply #19 on: October 31, 2009, 11:05:31 am »
baapre!!!
still that question been discussed!!
read the previous posts clealy!!!

man!!

By the way sorry for being too rude!!!
« Last Edit: October 31, 2009, 11:08:29 am by ~~~~shreycool~~~~ »
Logged
Friendship is like peeing on yourself. Everyone can see it but only you get the warm feeling that it gives :D :P :)

Alpha

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #20 on: October 31, 2009, 01:31:37 pm »
Ah yes...


x is between 2 and 4 or equal to 4...  I misplaced the order... 2 < x <= 4


I guess am owing them   :P

My excuses....  :)
Logged

Offline ~~~~shreyapril~~~~

  • SF Master
  • ******
  • Posts: 2606
  • Reputation: 2640
  • Gender: Male
  • "Prototype"
Re: IGCSE Maths doubt(paper 4)
« Reply #21 on: October 31, 2009, 01:33:03 pm »
ya the ans is now correct!!
By the way u taken add. math or not??

just to ans my doubts!!
Logged
Friendship is like peeing on yourself. Everyone can see it but only you get the warm feeling that it gives :D :P :)

Alpha

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #22 on: October 31, 2009, 02:02:36 pm »
Add Maths... yea.


Hey... what doubts??  :P
Logged

Offline ~~~~shreyapril~~~~

  • SF Master
  • ******
  • Posts: 2606
  • Reputation: 2640
  • Gender: Male
  • "Prototype"
Re: IGCSE Maths doubt(paper 4)
« Reply #23 on: October 31, 2009, 02:03:45 pm »
7 The position vectors of points A and B, relative to an origin O, are 2i + 4j and 6i + 10j respectively.
The position vector of C, relative to O, is ki + 25j, where k is a positive constant.
(i) Find the value of k for which the length of BC is 25 units. [3]
(ii) Find the value of k for which ABC is a straight line. [3]

l\just the last part!!!

rest is easy!!!
Logged
Friendship is like peeing on yourself. Everyone can see it but only you get the warm feeling that it gives :D :P :)

nid404

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #24 on: October 31, 2009, 02:13:52 pm »
I don't take add math as yet......but anyway can u put the answer up....so I can crosscheck...I will know if  am doing it correctly
Logged

Alpha

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #25 on: October 31, 2009, 02:23:55 pm »
Quote from: ~~~~shreycool~~~~ on October 31, 2009, 02:03:45 pm
7 The position vectors of points A and B, relative to an origin O, are 2i + 4j and 6i + 10j respectively.
The position vector of C, relative to O, is ki + 25j, where k is a positive constant.
(i) Find the value of k for which the length of BC is 25 units. [3]
(ii) Find the value of k for which ABC is a straight line. [3]

l\just the last part!!!

rest is easy!!!


If ABC is a str. line,

     AB = hBC, where h is a constant.

AB= OB- OA

BC = OC - OB

Continues in the attachment... I allways have problem explaining answers here... Formatting is confusing... Anyway, see the attachment.
« Last Edit: October 31, 2009, 02:26:55 pm by ~Alpha »
Logged

nid404

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #26 on: October 31, 2009, 02:35:01 pm »
the 2nd part is right....even I got 16 using gradient formula......should the first 1 be found using th distance formula....i dunno...im askin cuz i didn't take add math for my igs...
Logged

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
Re: IGCSE Maths doubt(paper 4)
« Reply #27 on: October 31, 2009, 03:00:39 pm »
Quote from: ~~~~shreycool~~~~ on October 31, 2009, 02:03:45 pm
7 The position vectors of points A and B, relative to an origin O, are 2i + 4j and 6i + 10j respectively.
The position vector of C, relative to O, is ki + 25j, where k is a positive constant.
(i) Find the value of k for which the length of BC is 25 units. [3]
(ii) Find the value of k for which ABC is a straight line. [3]

l\just the last part!!!

rest is easy!!!

ok..

first. --> AB=OB - OA = 4i + 6j

--> BC = OC - OB = (k-6)i + 15j

BC = x(AB)

(k-6)i + 15j = 4xi + 6xj

k-6 = 4x
6x = 15

x = 2.5

--

k-6 = 4*2.5 = 10

therefore --> k =16

Logged
divine intervention!

nid404

  • Guest
Re: IGCSE Maths doubt(paper 4)
« Reply #28 on: October 31, 2009, 03:05:01 pm »
why can't u use distance formula here ???
Logged

Offline Ghost Of Highbury

  • O_o_O lala!
  • SF Farseer
  • *******
  • Posts: 4096
  • Reputation: 41428
  • Gender: Male
  • Namaskaram!
Re: IGCSE Maths doubt(paper 4)
« Reply #29 on: October 31, 2009, 03:10:29 pm »
Quote from: ~Alpha on October 31, 2009, 02:23:55 pm

If ABC is a str. line,

     AB = hBC, where h is a constant.

AB= OB- OA

BC = OC - OB

Continues in the attachment... I allways have problem explaining answers here... Formatting is confusing... Anyway, see the attachment.


@nid - show how did u use the distance formula?

-----
BC = k-6)i + 15j

sqrt((k-6)^2 + 15^2) = 25

therefore

(k-6)2 = 252 - 152 = 400

k-6= sqrt(400) = 20

hence, k = 26
Logged
divine intervention!
Pages: 1 [2] 3 4 ... 7   Go Up
« previous next »