# C4 vectors questionWatch

#1
Stuck on the last question (q8) and have no clue how to go about starting.
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1 year ago
#2
(Original post by Aweevee)
Stuck on the last question (q8) and have no clue how to go about starting.
Maybe a quick sketch might prove to be useful.
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1 year ago
#3
(Original post by Aweevee)
Stuck on the last question (q8) and have no clue how to go about starting.
start by finding out the angles between the lines of the quadrilateral, and then find out the line lengths.

You should then be able to work out what the shape is, eg. a square will have two pairs of parallel lines and all the lines will be the same length
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1 year ago
#4
DGB and HAF are right angles so...
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1 year ago
#5
start by finding out the angles between the lines of the quadrilateral, and then find out the line lengths.

You should then be able to work out what the shape is, eg. a square will have two pairs of parallel lines and all the lines will be the same length
Q8 not Q6
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1 year ago
#6
(Original post by RDKGames)
Q8 not Q6
Ah yeah, reading things is not exactly my strong point
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#7
I figured out parts a and c but still struggling with part b
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1 year ago
#8
I'm in year 12 and we are doing this currently. ???? It used to be in c4?
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#9
Probably depends what exam board you're doing
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1 year ago
#10
(Original post by Aweevee)
I figured out parts a and c but still struggling with part b
Well the centre must be a point half way through one of the diagonals in the cube, doesn't it?
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1 year ago
#11
(Original post by mariejuana)
I'm in year 12 and we are doing this currently. ???? It used to be in c4?
Spec changed, this isn't anything more difficult with the right prerequisites.
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#12
(Original post by RDKGames)
Well the centre must be a point half way through one of the diagonals in the cube, doesn't it?
Ive tried working out the midpoints of diagonals but im getting the wrong answer
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1 year ago
#13
(Original post by Aweevee)
Ive tried working out the midpoints of diagonals but im getting the wrong answer
Let's see the attempt then and figure out where you're going wrong.
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#14
Figured it out, i was using a wrong arrangement of letters on the cube. so annoyed with myself
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1 year ago
#15
(Original post by Aweevee)
i figured out why i got wrog answer. I made a silly mistake with the arrangements of letters on cube, im so annoyed with myself
CF is NOT the diagonal across the cube.

Notice that , and - this means that A,C are on the same face of the cube. You are looking for two vectors where the distance between the two is

Spoiler:
Show

Why must the diagonal be that length? Well take a unit cube. The diagonal of it is length (check it), then just scale every length by 33 to get your cube.

EDIT: Nevermind, at least you got there
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