Find the Sum or Difference of Two Matrices - Pre-Calculus

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Question

Given the following matrices, what is the product of and ?

Answer

When subtracting matrices, you want to subtract each corresponding cell.

Now solve for and

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Question

Subtract:

Answer

In order to subtract matrices, they have to be of the same dimension. In this case, they are both 2x2.

The formula to subtract matrices is as follows:

Using this formula we plug in our values and solve:

8

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Question

Subtract:

Answer

In order to subtract matrices, they have to be of the same dimension. In this case, they are not. One is 2x2 while the other is 2x1.

As such, we cannot find their difference.

The answer is No Solution.

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Question

Add:

Answer

In order to add matrices, they have to be of the same dimension. In this case, they are both 2x2.

The formula to add matrices is as follows:

Plugging in our values to solve we get:

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Question

Add:

Answer

The first step in solving this problem is to multiply the matrix by the scalar. The formula is as follows:

In order to add matrices, they have to be of the same dimension.

In this case, they are both 2x2. So, we can then add the matrices together. The result is as follows:

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Question

Subtract

Answer

The first step in solving this problem is to multiply the matrix by the scalar.

We then have to make sure we can subtract the matrices.

In order to subtract matrices, they have to be of the same dimension. In this case, they are both 2x2.

Using our new matrix from multiplying the scalar and subtracting it from our other matrix we get the following:

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Question

We consider and defined as follows where they are supposed to be of order .

What is the sum of and ?

Answer

We can perform the addition since the matrices have the same sizes.

Looking at the first row of entries we get:

Note that any entry in the sum of is equal to .

Thus the sum becomes:

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Question

We consider the matrices and of the same size .

Find the sum .

Answer

Note: For addition of matrices, we do it componentwise.

Note: Adding the first two columns of and we obtain for every row of the first column of the resulting matrix.

In all other case, we obtain 0 everywhere. This gives the matrix:

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Question

We will consider the two matrices and given below. and are of the same size.

Find the sum

Answer

Adding componentwise (adding entry by entry) we obtain zeros everywhere except for the last row where we get to obain in every component of the row.

This gives the matrix:

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Question

We consider the following matrices:

Find .

Answer

To be able to subtract matrices, the matrices must have the same size.

A is 3x3 and B is 3x4. Therefore we can't perform this operation.

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Question

We consider the two matrice, find the sum .

Answer

Since A and B have the same size, we can perform addition.

The addition is performed componentwise.

The entry located at (i,j) of matrix A is added to the entry located at (i,j) of the matrix B.

In this case i=1 and j=1, 2 ,3 ,4,5

performing this operation we obtain:

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Question

We consider the matrices and given below. Find the sum .

,

Answer

Since A and B have the same size, we can perform addition.

The addition is performed componentwise.

The entry located at (i,j) of matrix A is added to the entry located at (i,j) of the matrix B.

Performing this operation we obtain:

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Question

For the matrices below, find the sum ( and are assumed to have the same size) . is assumed to be an odd positive integer.

Answer

Since we are assuming that the two matrices have the same size, we can performthe matrices addition.

We know that when adding matrices, we add them componenwise. Let (i,j) be any entry of the addition matrix. We add the entry from A to the entry from B:

since the entries from A are the same and given by 1 and the entries from B are the same and given by , we add these two to obtain :

and we know that m is odd integer, hence .

Therefore the entry of the sum matrix is 0

Therefore our matrix is given by:

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Question

Simplify:

Answer

Matrix addition is very easy! All that you need to do is add each correlative member to each other. Think of it like this:

Now, just simplify:

There is your answer!

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Question

Simplify:

Answer

Matrix addition is really easy—don't overthink it! All you need to do is combine the two matrices in a one-to-one manner for each index:

Then, just simplify all of those simple additions and subtractions:

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Question

If , what is ?

Answer

You can treat matrices just like you treat other members of an equation. Therefore, you can subtract the matrix

from both sides of the equation. This gives you:

Now, matrix subtraction is simple. You merely subtract each element, matching the correlative spaces with each other:

Then, you simplify:

Therefore,

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Question

Let

Determine the sum .

Answer

Since the dimensions of the two matrices are equal the sum of the two matrices exists.

To find the sum, add each component entry from the first matrix to the same component entry of the second matrix.

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Question

Let

Determine the sum .

Answer

Because the dimensions of the two matrices are not equal

(A 2x2 matrix is not of the same dimension as a 3x2 matrix)

The sum does not exist.

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Question

Answer

To find the difference between two matrices with the same dimensions, we simply subtract each entry from the right matrix from the corresponding entry of the left matrix. After performing the operation 9 times, we get the following matrix:

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Question

Answer

To find the sum of two matrices, we simply add each entry from one matrix to the corresponding entry of the other matrix, and the result becomes the entry in the same location of the matrix for their sum:

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