Math Terms - Visually Described ?

Bob · 2011-01-23 05:47:44

hi Superlynx

I think you should be doing

For this example there is a short cut that will get you to zero much more quickly. Post back if you want to know more.

Bob

Last edited by Bob (2011-01-23 05:50:03)

SuperLynx · 2011-01-23 06:57:54

How are you picking those numbers out ? Break it down a little further, afterwards I want to show you something related to Geometry math, both co-inside with each other so I hope you can help as well.

Bob · 2011-01-23 07:34:31

hi Superlynx

In post 272 I just took your line

and inserted multiplication signs.

aei means 'a' times 'e' times 'i'

So it was just that you had misunderstood the meaning of the formula.

Hope that clears it up for you.

By all means post a geometry question, but can I suggest you start a new thread with a title that fits that problem? This will make it easier for me and others to pick it up and help.

Bob

Last edited by Bob (2011-01-23 07:36:55)

SuperLynx · 2011-01-23 11:32:46

The rule I had posted in message #272 is the rule that must be followed to find the determent of a matrix ? I find it odd that there is no sequence to finding the determent, it seems like a random rule.

I've started another thread on the Geometry question as well.

bobbym · 2011-01-23 11:46:38

Hi SuperLynx;

That is not correct. There are other methods to finding the determinant. I gave you that formula because I know you cannot follow anything else just yet. I wanted you to learn how to plug in to a formula. You are lacking essential skills and it is crippling you.

It is obvious to me that your algebraic understanding is not up to the task yet. That is why I wanted you to learn how to follow a formula first.

I wanted you to be able to understand what a variable is. Jumping ahead is only making the task last longer. I do not mind, I like talking to you but what about you. You must get some fundamental math before you run to what a determinant and what it is good for.

I saw what you did up above. Concantenating numbers instead of multiplying them. You need to learn what an algebraic formula means. Now Bob, Howard and gAr do not need any help. They know algebra. Please ask the right questions when speaking to them.

SuperLynx · 2011-01-23 14:22:50

That is not correct. There are other methods to finding the determinant. I gave you that formula because I know you cannot follow anything else just yet. I wanted you to learn how to plug in to a formula. You are lacking essential skills and it is crippling you.
It is obvious to me that your algebraic understanding is not up to the task yet. That is why I wanted you to learn how to follow a formula first.

What you gave is one of many rules that can be used to find the determinant, that is what I wanted to know
For the time being I'll stick with this rule, what I'm curious about is why that rule is figured out as it is ?

I wanted you to be able to understand what a variable is. Jumping ahead is only making the task last longer. I do not mind, I like talking to you but what about you. You must get some fundamental math before you run to what a determinant and what it is good for.

I'm not jumping ahead, I'm trying to make sense of it my own way !

I saw what you did up above. Concantenating numbers instead of multiplying them. You need to learn what an algebraic formula means. Now Bob, Howard and gAr do not need any help. They know algebra. Please ask the right questions when speaking to them.

I am trying to learn what an algebraic formula means, I never said that bob, Howard, gAR needed help they were helping me and I had no problems with what they were saying like I said I was trying to make sense of it.

bobbym · 2011-01-23 14:30:03

I'm not jumping ahead, I'm trying to make sense of it my own way !

I did not say or said you said they needed help. They do not, you do. Let me help in the right way. You asked a question a while back how he did his determinants on that page. Let us do it, not jump ahead to more questions.

To make progress things have to be learned. You do not have to see the sense in things right now. You do not have to know how it is derived. That is way on the back burner, a long way off. You do not have to understand a formula to use it. Right now I would like you to learn how to use a formula I gave you in an earlier post.

Let me see how you compute the determinant.

All_Is_Number · 2011-01-23 16:15:31

SuperLynx wrote:

What I'm curious about is why that rule is figured out as it is ?

Perhaps writing the formula the following way will make the pattern more obvious and the formula easier to remember:

Notice that if you drew a diagonal line from left to right, top to bottom, through the first element of the first row, the second element of the second row, and the third element of the third row, it would pass through

, , and . Also notice that the first term of the formula is .

Now, draw another diagonal line, parallel to the first, starting at the second element of the first row, the third element of the second row, and (by wrapping around), the first element of the third row. That line passes through

, , and by wrapping around, through . Notice the second term is .

Next, draw another diagonal line, parallel to the first two, starting at the third element of the first row, the first element of the second row (by wrapping around), and the second element of the third row. That line passes through

, and, by wrapping around, through , and . Notice the third term is .

Now, let's draw more diagonal lines, but this time we'll draw them from top to bottom, right to left. (It might be helpful to use a different color pen for these lines.)

Start with the third element of the first row. Draw a line through the second element of the second row, and the first element of the first row. That line should pass through

, , and . Notice the fourth term in the formula is .

Similarly, draw a diagonal line through

, , and, by wrapping around, through . Notice the fifth term in the formula is .

Finally, draw a diagonal line through

, and, by wrapping around, through and . Notice the sixth term in the formula is .

Also notice that all of the terms obtained from diagonal lines that run from top to bottom, left to right, are added in the formula. All of the terms obtained from diagonal lines that run from top to bottom, right to left, are subtracted from the formula.

Last edited by All_Is_Number (2011-01-23 16:39:12)

SuperLynx · 2011-01-23 17:29:35

All is number - That was more helpful it is a little awkward way to figure out how to do the math for a matrix, is there an acronym/abbreviation that one can remember for this, but I know there are many other ways to figure out a matrix

I want to squeeze in a question about 4x4 matrix which is the following, how does 4x4 matrix come into use in geometry ? What is that extra row and column come into play ? If a 3x3 Matrix converted to scale of a geometric object of the first column that would be sX, sY, sZ that I understand.

All_Is_Number · 2011-01-23 19:49:35

SuperLynx, that's the trick I use to remember the formula for 3×3 matrices. There are some tricks to make finding the determinant easier on larger matrices, but I don't recall exactly what they are at the moment. I'd have to reference my old Linear Algebra text, which isn't handy. I don't remember them because I don't manipulate matrices by hand regularly, and linear algebra is far less intuitive than working with scalars.

If you want to learn about them, your best option might be to find your own text. You should be able to find an old edition for very little money, and it would likely be more productive than trying to find the information in Internet forums.

Once upon a time, my College Algebra professor once told us that manipulating matrices is something we would likely never want to do by hand, that calculators and computers are much better suited for the task. While my Linear Algebra didn't share that sentiment, I've found it to be generally true.

Personally, I'm a big fan of R (the free, open source statistical software package), which is designed for manipulating large matrices.

SuperLynx · 2011-01-24 00:38:49

SuperLynx, that's the trick I use to remember the formula for 3×3 matrices. There are some tricks to make finding the determinant easier on larger matrices, but I don't recall exactly what they are at the moment. I'd have to reference my old Linear Algebra text, which isn't handy. I don't remember them because I don't manipulate matrices by hand regularly, and linear algebra is far less intuitive than working with scalars.

Should I stick with this trick for now or is their an easier one ?

If you want to learn about them, your best option might be to find your own text. You should be able to find an old edition for very little money, and it would likely be more productive than trying to find the information in Internet forums.

I've look for something I can understand, no such luck. What are determents anyhow ?

Once upon a time, my College Algebra professor once told us that manipulating matrices is something we would likely never want to do by hand, that calculators and computers are much better suited for the task. While my Linear Algebra didn't share that sentiment, I've found it to be generally true.
Personally, I'm a big fan of R (the free, open source statistical software package), which is designed for manipulating large matrices.

'R' ?!?!? My goal to learn matrices is I want to understand them for use in geometry and how they are used to manipulate geometry, I have a little easier understanding of 3x3 matrices but not of 4x4.

I would like to know was the answer I posted in #284 correct ?

Bob · 2011-01-24 01:02:38

hi Superlynx,

Determinant short cuts at

http://www.mathedup.co.uk/Key_stage_5_FP4.htm

Click the 'Manipulating determinants' link

It's a PowerPoint.

Bob

Bob · 2011-01-24 01:07:07

hi again,

The link above that one is good too for how to find a det.

B

SuperLynx · 2011-01-24 01:35:58

I don't have powerpoint.

Bob · 2011-01-24 01:55:43

Oh drat!

They are good explanations. Any chance of viewing them on someone's computer?

Bob

All_Is_Number · 2011-01-24 11:42:51

SuperLynx wrote:

I don't have powerpoint.

Sign up for a free Live.com email address, which will give you access to Microsoft's online version of Office. Google has an online productivity suite that opens PowerPoint files, also.

Alternately, you can download OpenOffice.org for free, which runs on Windows, Mac OS X, and Linux operating systems.

All_Is_Number · 2011-01-24 12:07:05

SuperLynx wrote:

'R' ?!?!? My goal to learn matrices is I want to understand them for use in geometry and how they are used to manipulate geometry.

R would work very well for that, in combination with geometry related resources that tell what matrix operations and manipulations need to be performed for the geometry manipulations you wish to perform.

I've look for something I can understand, no such luck.

Linear algebra is a fairly advanced topic. If one hasn't mastered the recommended prerequisite topics, the subject matter can be extremely challenging. (It isn't necessarily easy even if you have mastered prerequisite material.)

I would like to know was the answer I posted in #284 correct ?

No, not for the matrix A given in post #282, where a = 1, b = 2, , i = 9.

SuperLynx · 2011-01-26 12:34:47

R would work very well for that, in combination with geometry related resources that tell what matrix operations and manipulations need to be performed for the geometry manipulations you wish to perform.

What is this R program you speak of ???:)

Linear algebra is a fairly advanced topic. If one hasn't mastered the recommended prerequisite topics, the subject matter can be extremely challenging. (It isn't necessarily easy even if you have mastered prerequisite material.)

I can see, but I'm going to give it my best the PowerPoint tutorials that Bob Bundy posted some of them are quite good, does anyone have any more PowerPoint tutorials on a wide range of math subjects ?

No, not for the matrix A given in post #282, where a = 1, b = 2, , i = 9.

I don't understand what you mean, even though my answer is wrong As I watch some of these power point tutorials when I have questions I will post using latex to get my question more clearly written

bobbym · 2011-01-26 13:28:57

Hi SuperLynx;

I can see, but I'm going to give it my best the PowerPoint tutorials that Bob Bundy posted some of them are quite good, does anyone have any more PowerPoint tutorials on a wide range of math subjects ?

I am glad that Bob and All_Is_Number have convinced you to get some background math. Good luck and study hard!

All_Is_Number · 2011-01-26 14:13:43

SuperLynx wrote:

What is this R program you speak of ???:)

From the Wikipedia article (bold face emphasis mine)
http://en.wikipedia.org/wiki/R_Statistics :

R is a programming language and software environment for statistical computing and graphics. The R language has become a de facto standard among statisticians for the development of statistical software, and is widely used for statistical software development and data analysis.

Although R is mostly used by statisticians and other practitioners requiring an environment for statistical computation and software development, it can also be used as a general matrix calculation toolbox with performance benchmarks comparable to GNU Octave or MATLAB.

Statistics relies heavily on matrices, because they can greatly simplify things. For example, when performing linear regression analysis, many of the matrix form equations are identical, whether one predictor variable is used, or 10,000 predictor variables are used. R handles matrices extremely well and simply. For example, obtaining the determinant of a 100×100 matrix (or even much larger matrices) named X is as simple as typing "det(X)".

Note that R is for numerical analysis and is not a computer algebra system.

R is very powerful, and free (compare to S-Plus, at $2399 per year or to SAS, at $6000 per seat). It is available for Windows, Mac OS X, and Linux in binary form (i.e., just download and install), and the source code is available for compiling on other platforms.

To learn more and to download R, see:

http://cran.r-project.org/

Last edited by All_Is_Number (2011-01-26 14:24:25)

Math Is Fun Forum

#276 2011-01-23 05:47:44

Re: Math Terms - Visually Described ?

#277 2011-01-23 06:57:54

Re: Math Terms - Visually Described ?

#278 2011-01-23 07:34:31

Re: Math Terms - Visually Described ?

#279 2011-01-23 11:32:46

Re: Math Terms - Visually Described ?

#280 2011-01-23 11:46:38

Re: Math Terms - Visually Described ?

#281 2011-01-23 14:22:50

Re: Math Terms - Visually Described ?

#282 2011-01-23 14:30:03

Re: Math Terms - Visually Described ?

#283 2011-01-23 16:15:31

Re: Math Terms - Visually Described ?

#284 2011-01-23 17:29:35

Re: Math Terms - Visually Described ?

#285 2011-01-23 19:49:35

Re: Math Terms - Visually Described ?

#286 2011-01-24 00:38:49

Re: Math Terms - Visually Described ?

#287 2011-01-24 01:02:38

Re: Math Terms - Visually Described ?

#288 2011-01-24 01:07:07

Re: Math Terms - Visually Described ?

#289 2011-01-24 01:35:58

Re: Math Terms - Visually Described ?

#290 2011-01-24 01:55:43

Re: Math Terms - Visually Described ?

#291 2011-01-24 11:42:51

Re: Math Terms - Visually Described ?

#292 2011-01-24 12:07:05

Re: Math Terms - Visually Described ?

#293 2011-01-26 12:34:47

Re: Math Terms - Visually Described ?

#294 2011-01-26 13:28:57

Re: Math Terms - Visually Described ?

#295 2011-01-26 14:13:43

Re: Math Terms - Visually Described ?

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