The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

GCSE Vectors

Scroll to see replies

Original post by junayd1998
Yeah lmao just hit me up on that question lmao. Na but anyways what did you do to learn Vectors any particular good video?


Unfortunately I just had a good teacher who taught it to us well so I don't have any video to suggest. I'm sure YouTube would have some good videos, you'll just have to search for a bit to find one.

Even if you type in "GCSE vectors" on Google there will be some information on it. :u:
http://prntscr.com/b14ka0

Like for example this question, I only understand we are going from O to M but how do we figure out the letter between O and M and M and G?
Reply 22
Avatar for Zacken
Zacken
22
Original post by junayd1998
http://prntscr.com/b14ka0

Like for example this question, I only understand we are going from O to M but how do we figure out the letter between O and M and M and G?


Basically, with vectors you can kind of trace along a path with your fingers.

So, for example - if you want to go from O to G,that's just from O to P and then from P to G.

Which is just OG = a + b.

Now you want half of OG, that is the midpoint, well - you know what OG is, so to find the midpoint, what do you do?
Original post by junayd1998
http://prntscr.com/b14ka0

Like for example this question, I only understand we are going from O to M but how do we figure out the letter between O and M and M and G?


So M is the midpoint of OG and we know that OG is a+b. Therefore, OM is half of a+b so the answer (I think) is 1/2a+1/2b (or 0.5a+0.5b or 1/2(a+b) )
(edited 7 years ago)
Original post by Zacken
Basically, with vectors you can kind of trace along a path with your fingers.

So, for example - if you want to go from O to G,that's just from O to P and then from P to G.

Which is just OG = a + b.

Now you want half of OG, that is the midpoint, well - you know what OG is, so to find the midpoint, what do you do?


So you can do a+b divided by 2?
Reply 25
Avatar for Zacken
Zacken
22
Original post by junayd1998
So you can do a+b divided by 2?


Yeah.
Original post by Zacken
Yeah.


So your final answer a + b / 2 ??
Reply 27
Avatar for Zacken
Zacken
22
Original post by junayd1998
So your final answer a + b / 2 ??


Yeah.
Original post by Zacken
Yeah.



http://prntscr.com/b19mh7

How do you do this one part b)
Vectors almost always comes up in the Maths paper, so from probability, you should try to get your head around it.
Original post by Fractite
Vectors almost always comes up in the Maths paper, so from probability, you should try to get your head around it.


Yeah I know im trying tends to be the last question on the edexcel maths paper either that or graph transformations
Reply 31
Avatar for Zacken
Zacken
22
Original post by junayd1998
http://prntscr.com/b19mh7

How do you do this one part b)


You want to show that NM is parallel to MC. So find NM, find MC - show that they are multiples of one another.
Proving straight lines in vectors just means that you have to show that the NM vector is a multiple of the NC vector and start at the same point (which they do, becuase they start at N).

You work out the NC vector, and then then NM vector, then divide them by each other (NC divided by NM) and it should give you a whole number, proving that they're a multiple of each other, and that NMC is a straight line.

If that makes sense.
Reply 33
Avatar for Notnek
Notnek
21
Original post by junayd1998
http://prntscr.com/b19mh7

How do you do this one part b)

If you prove that NM→\overrightarrow{NM} is parallel to NC→\overrightarrow{NC} then this proves that NMCNMC is a straight line.

To see why this must be true, draw a line NMNM anywhere on a peice of paper. Then try to draw a line NCNC on the paper such that NCNC is parallel to NMNM.

EDIT : Zacken's way is also fine.
(edited 7 years ago)
Original post by Zacken
You want to show that NM is parallel to MC. So find NM, find MC - show that they are multiples of one another.


Okay so N to M is b + 1/2BP ??
Reply 35
Avatar for Zacken
Zacken
22
Original post by junayd1998
Okay so N to M is b + 1/2BP ??


Find it all in terms of a and b.
Reply 36
Avatar for Zacken
Zacken
22
Original post by Fractite
Proving straight lines in vectors just means that you have to show that the NM vector is a multiple of the NC vector and start at the same point (which they do, becuase they start at N).

You work out the NC vector, and then then NM vector, then divide them by each other (NC divided by NM) and it should give you a whole number, proving that they're a multiple of each other, and that NMC is a straight line.

If that makes sense.


It doesn't - you can't divide vectors and it's also not necessary that they be integer multiples. They need only be real multiples of one another.
Original post by Zacken
It doesn't - you can't divide vectors and it's also not necessary that they be integer multiples. They need only be real multiples of one another.


Oh yeah.
Sorry.
Original post by Zacken
Find it all in terms of a and b.


Ugh im confused so we know N to P is b then P to M is what??

If we know A to P is 3b that means P to M is -1.5b? because its half?:s-smilie::frown:
Reply 39
Avatar for Zacken
Zacken
22
Original post by junayd1998
Ugh im confused so we know N to P is b then P to M is what??

If we know A to P is 3b that means P to M is -1.5b? because its half?:s-smilie::frown:


You know what PB is, PM is half of PB. Which isn't -1.5b.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you