Hard Light Productions Forums
Off-Topic Discussion => General Discussion => Topic started by: adwight on May 21, 2003, 06:04:37 pm
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I totally forget how to multiply matrices, and I have a final tomorrow, and half the test is on it. Can you help me??? Just walkthrough a problem, like this:
[-2 1] [4 2]
[3 0] x [-1 6]
I can't remember how to multiply those matrices. (They're 2x2 btw, the one on the left and the other on the right.) Thank you!!!
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You haven't posted since Christmas Eve, and you expect us to help you?!? HAH! :D
I would help, but I haven't a clue.
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Bah, shut up... I have too, just not in this forum. I've been too busy, but I'm coming around. Please someone help me!!!(I'm desperate, I don't want to fail.)
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Nobody wants to fail, but these things happen. :D
Anyway, where's CP when you need him?
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Half the test is on just matrix multiplication?
Anyway, here's how...
[ a b ] x [ e f ]
[ c d ] [ g h ]
equals
[ ae + bg af + bh ]
[ ce + dg cf + dh ]
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Hmm.... believe it or not, I've not once ever gone over matrices in any of my mathematics classes. :sigh:
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See! They never teach you anything even remotely useful.
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Originally posted by Joey_21
Hmm.... believe it or not, I've not once ever gone over matrices in any of my mathematics classes. :sigh:
pretty much same here, they don't teach us proper linear algebra 'til college. I just learn it on my own :p
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They did some basics of the matrix multiplication stuff in precalculus for me. That course was kind of weird, as they do a little bit of stuff from several topics without going into any of the topics in depth. :p
as for the original question, in general if AB=C (A is an i´m matrix and B is an m´j one), then C is an i´j matrix with elements Cij = åk=1m-1AikBkj where the Aij thing means the element in the i-th row and j-th column.
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hmm my post got cut off in the middle for some reason and it won't let me edit it... :wtf:
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So post again. :nod:
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So, what's the answer geniuses... jk
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as for the original question, in general if AB=C (A is an i´m matrix and B is an m´j one), then C is an i´j matrix with elements Cij = åk=1m-1AikBkj where the Aij thing means the element in the i-th row and j-th column.
Pass the bazooka.
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[-2 1] [4 2]
[3 0] x [-1 6]
__________________________________________________
The first one's answer is: [-8 , 2]
The second one: The answer is 18, I think. That x is not for multiplication, it is read as ordinary x and that operation is waaay different from the first one.
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Originally posted by Goober5000
...matrix multiplication...
:nervous:
They're coming....!
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Originally posted by Razor
Pass the bazooka.
__________________________________________________
[-2 1] [4 2]
[3 0] x [-1 6]
__________________________________________________
The first one's answer is: [-8 , 2]
The second one: The answer is 18, I think. That x is not for multiplication, it is read as ordinary x and that operation is waaay different from the first one.
you're on drugs, aren't you?
goober5k already provided the method for calculating it.
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Originally posted by kode
you're on drugs, aren't you?
From Kode's signature: I'm a glue addict.
Really? Look who's talking :lol: By the way, check this out (www.albinoblacksheep.com/flash/you.html )
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Originally posted by Razor
Really? :lol: By the way, check this out (www.albinoblacksheep.com/flash/you.html )
umm, yeah. that's really mature.
I just wish I had flash so it worked, dumbwit.
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umm, yeah. that's really mature.
:nod:
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Whats so funny about a moving "You are an idiot" window? You just close it and its gone. Now if there would be a popup bomb behind it, it might be fun to get people you dislike to click it :p
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Originally posted by Tiara
Whats so funny about a moving "You are an idiot" window? You just close it and its gone. Now if there would be a popup bomb behind it, it might be fun to get people you dislike to click it :p
That's exactly the point. It's a multiplying bomb.
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When you close it, about a dozen smaller versions of it pop up everywhere, along with a dialogue box saying "you are an Idiot" with an OK button.
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?
Didn't see that. Well, I guess I'm not an idiot :D
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it might all depend on your browser. What is it?
And if you have some sort of anti-popup program, I suppose that'd stop it.
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Got IE and Opera. Used IE for this. And I do have a anti popup. Its a very nice and simple program indeed :)
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What's it called? Might I be able to get a trial version of it?
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http://www.webknacks.com
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http://www.webwasher.com/
http://www.mozilla.org/