Inverse matrix word problem, matrix arithmetic

In summary: The Attempt at a SolutionDo not post thumbnails; they cannot be read on some media. Just type out the problem and your solution work; it should not take long and is not much trouble.Your set up is correct.Do you not know how to invert a matrix, say, by "row operations"?You say you get "inconvenient numbers".Do you mean just awkward fractions?The fact that the arithmetic is hard shouldn't stop you.If nothing else, you can use decimal arithmetic on a calculator, rounding to, say, three or four decimal places.
  • #1
IrinaK.
33
0

Homework Statement


Hello!
Please, take a look at the attached picture - there is a quote of the exercise and below is my attempt to make a matrix. Is my matrix correct? I have tried many times to convert it to inverse one, but I can't figure out how to do it - I keep getting "inconvenient" numbers that do not further lead to correct answers for x, y and z.

Thank you!

Homework Equations

The Attempt at a Solution

 

Attachments

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    Screen Shot 2014-09-28 at 12.51.33 PM.png
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  • #2
IrinaK. said:

Homework Statement


Hello!
Please, take a look at the attached picture - there is a quote of the exercise and below is my attempt to make a matrix. Is my matrix correct? I have tried many times to convert it to inverse one, but I can't figure out how to do it - I keep getting "inconvenient" numbers that do not further lead to correct answers for x, y and z.

Thank you!

Homework Equations

The Attempt at a Solution


Do not post thumbnails; they cannot be read on some media. Just type out the problem and your solution work; it should not take long and is not much trouble.
 
  • #3
Your set up is correct. Do you not know how to invert a matrix, say, by "row operations"? You say you get "inconvenient numbers". Do you mean just awkward fractions? The fact that the arithmetic is hard shouldn't stop you. If nothing else, you can use decimal arithmetic on a calculator, rounding to, say, three or four decimal places.
 
  • #4
Thank you :) Yes, you are right. It seems that I always miss a correct digit here and there. Here is what I came up with (without the last row completed)
 

Attachments

  • Screen Shot 2014-09-28 at 5.16.55 PM.png
    Screen Shot 2014-09-28 at 5.16.55 PM.png
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  • #5
Ray Vickson said:
Do not post thumbnails; they cannot be read on some media. Just type out the problem and your solution work; it should not take long and is not much trouble.
Actually, it was a rather big picture. Sorry about that.
 

FAQ: Inverse matrix word problem, matrix arithmetic

1. What is an inverse matrix?

An inverse matrix is a matrix that when multiplied with another matrix, results in the identity matrix. In other words, it "undoes" the original matrix. It is denoted by A-1.

2. How do I find the inverse of a matrix?

The inverse of a matrix can be found by using the Gauss-Jordan elimination method or by using the inverse matrix formula, which involves finding the determinant and cofactor matrix of the original matrix.

3. What is a word problem involving matrix arithmetic?

A word problem involving matrix arithmetic could be something like: "A bakery sells two types of muffins, blueberry and chocolate chip. On Monday, they sold 3 blueberry muffins and 4 chocolate chip muffins for a total of $12. On Tuesday, they sold 4 blueberry muffins and 2 chocolate chip muffins for a total of $10. What is the price of one blueberry muffin and one chocolate chip muffin?" This problem can be solved using a system of equations and matrix multiplication.

4. Can any matrix be inverted?

No, not all matrices can be inverted. In order for a matrix to be invertible, it must be square (i.e. have the same number of rows and columns) and have a non-zero determinant.

5. What is the practical application of inverse matrices and matrix arithmetic?

Inverse matrices and matrix arithmetic have many practical applications in fields such as physics, engineering, computer graphics, and economics. They can be used to solve systems of equations, find the best fit for a set of data, and perform transformations on geometric shapes.

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