Imagine Everything Posted November 26 Author Posted November 26 Hello Hello My pc has decided to go a bit weird, not sure what the issue is but I might not be able to post a lot in the next few days. If you don't hear from me much, that's why. Hopefully it won't be too long.
Imagine Everything Posted December 2 Author Posted December 2 Hello, Just a quick update, pc is still down Hope you're well.
Imagine Everything Posted December 5 Author Posted December 5 My pc is back again finally but needs some attention. The HD went mad and some data got lost / transferred And I need to do some catch up so I'll be back in a few days.
Imagine Everything Posted Sunday at 02:43 PM Author Posted Sunday at 02:43 PM (edited) Still have a fair bit of re reading and lectures to go through. Weird how much slipped from my head in just a week or so. If I haven't posted for a little while, it's just because I'm just catching up. Stay safe Edited Sunday at 02:43 PM by Imagine Everything
Imagine Everything Posted Monday at 05:00 PM Author Posted Monday at 05:00 PM (edited) I'm wading through as I said, the Khan lectures and at one point he is explaining the vectors & tupels and equasions of a + b and adds -4 + -4 together to make 4 which I don't really understand if this is being explained using something you posted Studiot and he is also posting in the lecture. What is it I'm not seeing? Edited Monday at 05:00 PM by Imagine Everything
studiot Posted Monday at 07:43 PM Posted Monday at 07:43 PM Let us change my diagram from the axes of a graph to this little story. My girlfriend and I live on either side of a crossroads. Fig A shows that I live 4 miles down East road at the end of the arrow. Fig B shows she lives 1 mile along West Street at the end of the arrow. How far must I walk to visit her ?
Imagine Everything Posted Monday at 08:02 PM Author Posted Monday at 08:02 PM (edited) 26 minutes ago, studiot said: Let us change my diagram from the axes of a graph to this little story. My girlfriend and I live on either side of a crossroads. Fig A shows that I live 4 miles down East road at the end of the arrow. Fig B shows she lives 1 mile along West Street at the end of the arrow. How far must I walk to visit her ? I understand the 4 + -1 being 5. Your diagram helped a lot with that ty, it was the trying to understand the -4 + -4 = 4 I can't get my head around. Do 2 minuses make a plus? In the Khan lecture he made that sum but in my mind both the minus 4's seem to be pointing in the negative. So wouldn't that make 8 and not 4? It was a 2 part sum, the -4 + -4 was the number at each of the tops of the the 2, 2 tupel columns. There was another sum involved for the bottom part of the vectors but I think I understood that. Edited Monday at 08:10 PM by Imagine Everything
Imagine Everything Posted Wednesday at 07:55 PM Author Posted Wednesday at 07:55 PM Still trawling through bits n pieces but this seemed interesting, I guess it's very similar to the vector matrix in IR2 (Khan Academy) but without the south direction. perpendicularity I know it's just explaining perpendicularity but I kind of envisage my 2 states next to each other idea as well with 'north' perhaps being the gap even though it's in a conserved system. Hope I said that right, still amazed at how much I forgot in just a week or so..damn pc...😠 And tbh, I don't know if I will get to grips with Orthogonality or not. It seems really complex. If I don't post much atm it's just because I'm trawling through still, I am here though I had a thought yesterday and I'll ask it as weird as it might sound. Could DM & gravity be the same thing? Maybe if it is trapped in an atmosphere it behaves differently to outside of an atmosphere? Pushing things down instead of pulling them down maybe?
studiot Posted Wednesday at 09:48 PM Posted Wednesday at 09:48 PM On 12/9/2024 at 8:02 PM, Imagine Everything said: I understand the 4 + -1 being 5. Your diagram helped a lot with that ty, it was the trying to understand the -4 + -4 = 4 I can't get my head around. Do 2 minuses make a plus? There are very many Khan videos. We need a link to the one you are referring to along with a time in the video to look at.
Imagine Everything Posted 12 hours ago Author Posted 12 hours ago Hey Studiot, here's the link to the video https://www.khanacademy.org/math/linear-algebra/vectors-and-spaces/vectors/v/linear-algebra-vector-examples It's at 24.44 or so where he adds -4 - -4 (I got the sum wrong, I thought it was addition) but still he says-4 - -4 = -4 +4 = 0 I think my problem is that he adds -4 when it states -4 - -4 Hope that makes sense. I'm a bit confused. If you can shed some light I'd be grateful. I know I'm doing the analogous equivalent of flying in space before I can walk with regards to maths. Oh and if I may ask, are nucleai specific to atoms or can electrons, protons and neutrons also have their own nucleai? Or perhaps more, like quarks?
Genady Posted 11 hours ago Posted 11 hours ago 46 minutes ago, Imagine Everything said: -4 - -4 = -4 +4 = 0 -4 - 4 = -8 -4 - 3 = -7 -4 - 2 = -6 -4 - 1 = -5 -4 - 0 = -4 -4 - -1 = -3 -4 - -2 = -2 -4 - -3 = -1 -4 - -4 = ? 1
Imagine Everything Posted 11 hours ago Author Posted 11 hours ago from what you posted Genady the answer must be 0 ? Thank you 1
studiot Posted 10 hours ago Posted 10 hours ago Just now, Imagine Everything said: Hey Studiot, here's the link to the video https://www.khanacademy.org/math/linear-algebra/vectors-and-spaces/vectors/v/linear-algebra-vector-examples It's at 24.44 or so where he adds -4 - -4 (I got the sum wrong, I thought it was addition) but still he says-4 - -4 = -4 +4 = 0 I think my problem is that he adds -4 when it states -4 - -4 Hope that makes sense. I'm a bit confused. If you can shed some light I'd be grateful. I know I'm doing the analogous equivalent of flying in space before I can walk with regards to maths. Oh and if I may ask, are nucleai specific to atoms or can electrons, protons and neutrons also have their own nucleai? Or perhaps more, like quarks? OK so I was able to see what the narrator was talking about. He did go through it very quickly, not only because he was distracted by a malfunctioning pen but also becasue the issue has nothing to do with vectors. It is more basic than that and stems from the problem many people have with signed numbers. you have two signed numbers viz minus 4 as well as minus 4 again. That is one use of the negative sign -4 ; -4 The signs belong with the numbers. they do not signify any operation at all, they are part of the (signed) number. Then you have an operation - in this case subtraction. So you have minus 4 take away (or subtract) minus 4 (-4) - (-4) So the negative sign inside the brackets is a different animal from the negative sign between the brackets. For the operation subtractio I recommend the rule To subtract - Change the sign od the second quantity and add to the first. minus 4 subtract minus 4 Change the sign and add So we have minus 4 add 4 (-4) - (-4) = (-4) + (4) = 0 does this help ?
Imagine Everything Posted 10 hours ago Author Posted 10 hours ago (edited) 22 minutes ago, studiot said: For the operation subtractio I recommend the rule What do you mean by rule Studiot? Is this a maths thing that I've not learnt? Are there rules in maths that I need to learn? Is it advanced maths? Any help is always appreciated. Edited 10 hours ago by Imagine Everything
studiot Posted 6 hours ago Posted 6 hours ago (edited) Just now, Imagine Everything said: Is this a maths thing that I've not learnt? Are there rules in maths that I need to learn? Is it advanced maths? Yes it looks like it. In mathematics there is nearly always more than one way to do something. No it is not advanced maths. I think somewhere in these many pages I have already mentioned signed numbers and sign conventions. There are plain 'ordinary' numbers we use for counting, measuring etc. They may be whole numbers or fractions. We use them for the four basic operations of arithmetic add - subtract - multiply - divide. But often we want our numbers to represent more than this. For instance up or down ; electrical positive or electrical negative ; clockwise or anticlockwise ; left or right and so on. To do this we establish a sign convention. The most common convention is that we attach a plus or minus to each and every number so the numbers we use are then called signed numbers. We do this because we can benefit from using the signed numbers in the same formulae we use for basic arithmetic. However in order to make this work we must learn some extra rules for these basic processes. The Kahn narrator is using signed numbers, not plain ordinary numbers in his column vectors. does this help ? Edited 6 hours ago by studiot
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