# Maths edexcel vector question

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#1
Question lifted from past edexcel paper .

OAN OMB and APB are straight lines. M is the midpoint of OB.
OA=a. Vector
OB=b. Vector.
AP(vector)=k x AB(vector) where k is a scalar quantity.

Given that MPN is a straight line find the value of k

Thanks
0
4 years ago
#2
I was doing that yesterday! Still working it out!
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#3
Something simple I'm missing..
Can I add a pic to the topic
0
4 years ago
#4
(Original post by Dm998)
Question lifted from past edexcel paper .

OAN OMB and APB are straight lines. M is the midpoint of OB.
OA=a. Vector
OB=b. Vector.
AP(vector)=k x AB(vector) where k is a scalar quantity.

Given that MPN is a straight line find the value of k

Thanks
I can't do this... Have you got the question down completely? Could you post a picture of it?

Also, you have to post what you've worked out/tried so far before people can help you.
0
4 years ago
#5
The answer is 2/5 but I keep getting -5/2
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#6
I'll add the question and working out if someone can tell me how to add an attachment
0
4 years ago
#7
(Original post by Dm998)
I'll add the question and working out if someone can tell me how to add an attachment
There are insert image and attachment buttons above the box you type in when you post.
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#8
Not on my screen
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#9
The answer is 2/5 but I keep getting -5/2
How are you tackling it?
0
4 years ago
#10
Working out MN And PN as well as PM
0
4 years ago
#11
(Original post by Dm998)
Not on my screen

https://imgur.com/b7PDxSM

This is the question? (you left out AN=2OA in your original post).
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#12
How can you work out any vectors involving P?
0
4 years ago
#13
You can thank ghostwalker
1
3 years ago
#14
AB=b-a
MN=-0.5b+a+3a
MN=4a-0.5b
MP=-0.5b+a+k(b-a)
MP=-0.5b+a+kb-ka
4/1-k=-0.5/-0.5+k (number of As in MN divided by As in MP = no. Bs in MN/Bs in MP)
8/2-2k=-1/-1+2k
8(-1+2k)=-1(2-2k)
-8+16k=-2+2k
14k=6
k=6/14
k=3/7
Hope that helps Last edited by doctorwhonerd42; 3 years ago
0
2 years ago
#15
AB = AO+OB
AB = -a+b
MN = MO+OA+AN
MN = -0.5b+a+2a
MN = 3a-0.5b
MP = MO+OA+AP
MP = -0.5B+a-ka+kb
NM = -3a+0.5b
NP = -2a+k(-a+b)
NPM is a straight line, so,
x × NP = NM
k = 2/5

Little late but correct
Last edited by Pro student; 2 years ago
1
1 year ago
#16
(Original post by Pro student)
AB = AO+OB
AB = -a+b
MN = MO+OA+AN
MN = -0.5b+a+2a
MN = 3a-0.5b
MP = MO+OA+AP
MP = -0.5B+a-ka+kb
NM = -3a+0.5b
NP = -2a+k(-a+b)
NPM is a straight line, so,
x × NP = NM
k = 2/5

Little late but correct
Can you please explain the last step ?Exactly how did you get the 2/5 . I do get other steps though
0
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