Final answer:
An upper triangular matrix has all elements below the main diagonal as zero, while a lower triangular matrix has all elements above the main diagonal as zero. To prove A + (B + C) = (A + B) + C, perform the operations on the matrices and compare the results.
Step-by-step explanation:
An upper triangular matrix is a square matrix where all the elements below the main diagonal are zero. A lower triangular matrix is a square matrix where all the elements above the main diagonal are zero.
To prove that A + (B + C) = (A + B) + C, we can perform the operations on the matrices:
- Add matrices B and C together
- Add matrix A to the result obtained from step 1
- This gives us the left-hand side of the equation
- Add matrices A and B together
- Add matrix C to the result obtained from step 4
- This gives us the right-hand side of the equation
- Compare the left-hand side and right-hand side to see if they are equal
By using this method, we can prove that A + (B + C) = (A + B) + C.