C4 vectors question Watch

Aweevee
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Stuck on the last question (q8) and have no clue how to go about starting. Name:  20171027_143113-compressed.jpg.jpeg
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RDKGames
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(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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Faction Paradox
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(Original post by Aweevee)
Stuck on the last question (q8) and have no clue how to go about starting. Name:  20171027_143113-compressed.jpg.jpeg
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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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GeorgeMillerr
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DGB and HAF are right angles so...
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RDKGames
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(Original post by Faction Paradox)
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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Faction Paradox
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(Original post by RDKGames)
Q8 not Q6
Ah yeah, reading things is not exactly my strong point
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Aweevee
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I figured out parts a and c but still struggling with part b :confused::confused::confused:
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mariejuana
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I'm in year 12 and we are doing this currently. ???? It used to be in c4?
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Aweevee
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Probably depends what exam board you're doing
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RDKGames
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(Original post by Aweevee)
I figured out parts a and c but still struggling with part b :confused::confused::confused:
Well the centre must be a point half way through one of the diagonals in the cube, doesn't it?
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RDKGames
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(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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Aweevee
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(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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RDKGames
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(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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Aweevee
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Figured it out, i was using a wrong arrangement of letters on the cube. so annoyed with myself
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RDKGames
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(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 |AB|=33, and |AC|=33\sqrt{2} - 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 33\sqrt{3}

Spoiler:
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Why must the diagonal be that length? Well take a unit cube. The diagonal of it is length \sqrt{3} (check it), then just scale every length by 33 to get your cube.



EDIT: Nevermind, at least you got there
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