YT2095 Posted October 16, 2003 Share Posted October 16, 2003 Hmmm... I can only picture 3 as well? 2 to make a cross + and one right through the middle to make like a "jack" type shape. also, Imaginary numbers is that what the RND key on a calculator is for, it makes random numbers (I always thought it was for statistics and stuff)? Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 Lynn said in post #25 : Sorry, I don't quite get it. 4 axes at right angles to each other, how could it happen in 3-dimentions? It couldn't. Lynn said in post #25 : Would it be 4-dimentions then? By definition. Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 YT2095 said in post #26 :Hmmm... I can only picture 3 as well? 2 to make a cross + and one right through the middle to make like a "jack" type shape. also, Imaginary numbers is that what the RND key on a calculator is for, it makes random numbers (I always thought it was for statistics and stuff)? Imaginary numbers are real numbers multiplied by i, the square root of minus 1 (bi, where b is real). Complex numbers are of the form a + bi, where a and b are real. Random numbers can be but usually AREN'T imaginary. Link to comment Share on other sites More sharing options...
YT2095 Posted October 16, 2003 Share Posted October 16, 2003 you mention `i` being the square root of -1 so is that a "constant"? as in every time you type that into a calc, it`ll give the same result? I`m curios now what makes that such a special number? why not sqr rt of -2 or 3 etc..? and by REAL numbers, do you mean things that you know are fact "the fence is 3.5m long" or real as in Whole numbers? (I`m kinda new to this). Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 Real numbers = any non imaginary number (ie from negative infinity to positive infinity. examples being, say, 312, 2314.1 and pi) What do you mean, is SQRT(-1) a constant? Does SQRT(2) change? It's SQRT(-1) because that's the simplest way of doing it. Why have the sqrt(-2) as i, and then have to worry about the fact that it's irrational? Why have sqrt(-4) as i, when you might just as well as have sqrt(-1), because all that you're doing is making i = 2i (regular). SQRT(-2) = SQRT(2)i (squaring both sides: -2 = 2 * i*i = -2 Oh, and calculators don't 'do' imaginary numbers. If you try to square root -1, you'll get an error. Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 MrL_JaKiri said in post #12 : It does if you have a 3 (or 4) dimensional graph with each set of axes being represented by an Argand Plane. Sorry for asking this question and I'm pretty sure it's a dumb one. But I am gonna ask this anyway- How can u have a four dimensional graph? And if u replace the 3 axis (in a 3d graph) with an Argand Plane then I can only imagine two planes. I was just curious if u draw a 4d graph (I am not sure if it is possible practically - so please don't laugh), will we get 3 planes? If we do, what's the function of it? And is there function (or existance) of a third axis in an Argand Plane. I thought it had only two axis intersecting each other - one representing the real numbers and one representing imaginary ones. And though it is not relevant - I was just curious - do u know what is a " Treserect " - I am not sure if the spelling is right - and not sure if something of this name really exists - but if it does - what is it? I have heard that this is four dimensional object which cannot be drawn on papers but u can draw the projection of its shadow. [ This may also be from a science-fiction book, so please don't blame me if it is. ] ( A side question - Can u define a point in the Argand Plane with the value of Pi - I mean a teacher of mine told us that u can never get Pi or e (exp) as a root of any equations - So I just had this crazy thought ) Please don't laugh at these questions - I'm sure these are dumb ones - but just had to ask them. Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 neo_maya said in post #31 : ( A side question - Can u define a point in the Argand Plane with the value of Pi - I mean a teacher of mine told us that u can never get Pi or e (exp) as a root of any equations - So I just had this crazy thought ) That's incorrect. Example. If the radius of a circle is 1/2(unit), what's the circumference? Reply to rest following. Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 neo_maya said in post #31 : How can u have a four dimensional graph? And if u replace the 3 axis (in a 3d graph) with an Argand Plane then I can only imagine two planes. I was just curious if u draw a 4d graph (I am not sure if it is possible practically - so please don't laugh), will we get 3 planes? If we do, what's the function of it? And is there function (or existance) of a third axis in an Argand Plane. I thought it had only two axis intersecting each other - one representing the real numbers and one representing imaginary ones. Well, you're mistaken about the number of planes in a 3d object. I can think of 3; xy, xz and yz. Similarly, in a 4d situation there will be 6 (xy, xz, xa, yz, ya, za). As for the function, it's to have a complex graph with 2 variables. (As I stated above, one direction for each of real x, imaginary x, real y, imaginary y). And as to the tesseract... If a square is the 2d version, and the cube is the 3d version, then the tesseract is the 4d version. We can view it in 3d (sort of) by perspective, similar to implying a 3d object in 2d. (I've seen one by this method.) A tesseract is more commonly known as a hypercube. Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 MrL_JaKiri said in post #33 : Well, you're mistaken about the number of planes in a 3d object. I can think of 3; xy, xz and yz. Similarly, in a 4d situation there will be 6 (xy, xz, xa, yz, ya, za). Oooooppppppppsss. Told ya I was dumb. But still can't think of the fourth axis (in a 4d situation). Three axis intersects each other (in 3d) perpendicularly, but 4d?? But what is the fourth dimension of a tesseract?( I always thought the fourth dimension was time ) I have just said something silly - haven't I? :scratch: Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 http://www.scienceforums.net/forums/showthread.php?s=&threadid=1068 Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 R u still there? I had some more questions? If u r free and not annoyed with all my dumb questions, may I please ask them? Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 Fire away. Even if I'm not here now, I can answer them later. And even if I don't, someone else will. Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 Thanks. First of all - http://dogfeathers.com/java/hyprcube.html What is this? (This is not the main question) Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 I am still reading the thread that u posted. But the problem is these stuff are way over my head. Trying.... Sorry for keeping u waiting - If u want I will write the questions and u can always answer them later. Thanks a lot. Did u go to the website? Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 This whole conception of dimensions is a bit confusing. U said we can have xy, xz, xa, yz, ya, za planes in a 4d situation, but what does the axis a stand for? Someone once told me that the fourth dimension is arbitrary - it can be time or something else (according to his will or according to the equation he is solving). Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 neo_maya said in post #38 :Thanks. First of all - http://dogfeathers.com/java/hyprcube.html What is this? (This is not the main question) It's an attempt to show a 4 dimensional object in 2 dimensions. As you can see, it doesn't work. Link to comment Share on other sites More sharing options...
YT2095 Posted October 16, 2003 Share Posted October 16, 2003 mr_l so `i` is a fixed number then? it`s the result of sqr rt -1 and no I did`nt know that a calculator wouldn`t do it (can you show how it`s worked out then? I wouldn`t know where to start) is `i` classed as a Function? ( I read about those in calculus threads) or is it a constant? neo-mayo, NOT knowing something here is fine, that`s partly why I`m here too, but PLEASE stop wearing it like a badge, if you want to know ask! Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 This Entropy thing is the most confusing of all. It's the operative of the thermal co-efficient of a closed system - what's that supposed to mean? dS = dQ/T (had some integration signs) I read somewhere that in a adiabatic process the change of entropy is 0 and that in a closed system it will keep increasing until the temperature of the whole universe is equal and since it is irreversible, we can't go back in time (though it is irrevlent here). My problem is that - I don't unnderstand the concept of entropy. (Actually I don't understand anything) and why is it irreversible? [ PS : There r a whole lot of things that I need to ask and all of these are surely some dumb questions. ] Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 YT2095 said in post #42 :and no I did`nt know that a calculator wouldn`t do it (can you show how it`s worked out then? I wouldn`t know where to start) You don't work it out, it's just.... i. The square root of -1. That's how its written. It's not going to be equal to 35 or something. Link to comment Share on other sites More sharing options...
JaKiri Posted October 16, 2003 Share Posted October 16, 2003 neo_maya said in post #43 :My problem is that - I don't unnderstand the concept of entropy. (Actually I don't understand anything) and why is it irreversible? The second law of thermodynamics states that within any closed system, entropy always increases. Entropy is basically a measure of how much energy in the system is not 'ordered' or useful; like when running a car, there's heat given off. As for the universe thing, that is correct. It is called the heat death of the universe. It is irreversable because no matter what action we take to increase order, there will be a subsequent larger increase in disorder (because entropy [disorder] cannot decrease in any closed system). (A closed system is basically something which is cut off from everything else. This part is essential, and is one of the bits of science ignored by creationists, but that's going off on a tangent) Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 I think it's like infinity - u can't define it - yet there it is - an infinite amount of infinity inside infinity [ At least that's how this crappy head sees it ] Link to comment Share on other sites More sharing options...
YT2095 Posted October 16, 2003 Share Posted October 16, 2003 that makes no sense at all whatsoever to me? Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 My last post was for YT. Link to comment Share on other sites More sharing options...
YT2095 Posted October 16, 2003 Share Posted October 16, 2003 neo-mayo, ok so it would fit into the "function" catagory then , yes? a bit like the reciprocal of 0 = infinity (or at least any number you choose to mention) Link to comment Share on other sites More sharing options...
neo_maya Posted October 16, 2003 Share Posted October 16, 2003 MrL_JaKiri said in post #45 : The second law of thermodynamics states that within any closed system, entropy always increases. Entropy is basically a measure of how much energy in the system is not 'ordered' or useful; like when running a car, there's heat given off. But if a certain amount of energy is not ordered or useful - then wouldn't that energy transform to some other form of energy? Then why is it irreversible? Link to comment Share on other sites More sharing options...
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