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What is the Inverse Property of Matrix Addition?
What is the Inverse Property of Matrix Addition?
Summary
- 'a' stands for any number
- If you add any number with its opposite, you'll always get zero
- A number's opposite is that number multiplied by -1
- A matrix's opposite is that matrix multiplied by the scalar -1
- 'A' stands for any matrix, and '-A' is its opposite
- The bold '0' represents the zero matrix, which will have the same dimensions as 'A' and '-A'

Notes
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- 'a' can be any number
- If you add any number with its opposite, you'll always get zero
- A number's opposite is that number multiplied by -1
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- A matrix's opposite is a matrix that has the same dimensions, but each element is replaced by its opposite
- A number's opposite is that number multiplied by -1
- This is the same as multiplying the entire matrix by the scalar -1
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- A zero matrix is a matrix with zeros as its elements
- A matrix's opposite is a matrix that has the same dimensions, but each element is replaced by its opposite
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- Elements with the same color are in the same position in their respective matrices
- A matrix's opposite is a matrix that has the same dimensions, but each element is replaced by its opposite
- Here we just multiplied each element by -1 to get its corresponding element in the opposite matrix
- Adding each set of corresponding elements gives us a matrix with 0 in every position!
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- When we added a matrix and its opposite we got a zero matrix, just like how we added a number and its opposite to get 0
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- Adding the opposite gives us a zero matrix in our example
- Will adding the opposite work for any matrix, not just our example?
- Remember, a matrix's opposite is a matrix of the same dimensions, but with opposite elements
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- If we can show that this works with variables, we can prove that the property holds in general!
- To get the opposite of this matrix, just change the sign in front of each variable in the matrix
- So we have -a, -b, -c, and -d as the elements in the opposite matrix
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- Just like before, when we add each number and its opposite we get 0
- This gives us a matrix with all zeros as its elements, or a zero matrix
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- Since the property worked for our general matrices, that means it holds for ALL matrices!
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- A zero matrix is a matrix whose elements are all zeros
- The opposite of 'A' is 'A' multiplied by the scalar -1