document.write( "Question 200366: Hi everyone I asked a similiar question recently but got no responce, I may have input the question incorrectly.
\n" ); document.write( "I need to solve the following Matrices and comment on the outcomes.
\n" ); document.write( "For the following:
\n" ); document.write( "A =
\n" ); document.write( "( 1 0 )
\n" ); document.write( " 0 1 \r
\n" ); document.write( "\n" ); document.write( "B =
\n" ); document.write( "( 2 1 )
\n" ); document.write( " 3 2 \r
\n" ); document.write( "\n" ); document.write( "C =
\n" ); document.write( "( 1 4 )
\n" ); document.write( " 3 -1
\n" ); document.write( " -2 5
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\n" ); document.write( "Find and state why or why not the following is possible.
\n" ); document.write( "i) AB
\n" ); document.write( "ii) B^1
\n" ); document.write( "iii) BC^T
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Algebra.Com's Answer #150703 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
i)\r
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\n" ); document.write( "\n" ); document.write( "Since the first matrix is a 2 by 2 matrix and the second matrix is a 2 by 2 matrix, this means that the resulting matrix will be a 2 by 2 matrix.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the final resulting matrix will look like:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2Cx%2Cx%2Cx%2Cx%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "note: the \"x\"s are just placeholders for now\r
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\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 1st row of the first matrix by the 1st column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "1st row, 1st column: \r
\n" ); document.write( "\n" ); document.write( "\"%281%29%2A%282%29%2B%280%29%2A%283%29=2%2B0=2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 1st row, 1st column of the resulting matrix is \"2\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C2%2Cx%2Cx%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 1st row of the first matrix by the 2nd column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "1st row, 2nd column: \r
\n" ); document.write( "\n" ); document.write( "\"%281%29%2A%281%29%2B%280%29%2A%282%29=1%2B0=1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 1st row, 2nd column of the resulting matrix is \"1\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C2%2C1%2Cx%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "================================================================================\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 2nd row of the first matrix by the 1st column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "2nd row, 1st column: \r
\n" ); document.write( "\n" ); document.write( "\"%280%29%2A%282%29%2B%281%29%2A%283%29=0%2B3=3\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 2nd row, 1st column of the resulting matrix is \"3\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C2%2C1%2C3%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 2nd row of the first matrix by the 2nd column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "2nd row, 2nd column: \r
\n" ); document.write( "\n" ); document.write( "\"%280%29%2A%281%29%2B%281%29%2A%282%29=0%2B2=2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 2nd row, 2nd column of the resulting matrix is \"2\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C2%2C1%2C3%2C2%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "==============================================================================\r
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\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Answer:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the solution is \"%28matrix%282%2C2%2C2%2C1%2C3%2C2%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In other words,\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "which means that \"AB=%28matrix%282%2C2%2C2%2C1%2C3%2C2%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "ii)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "If you raise ANY matrix to a power of 1, you'll get that same matrix as a result. So \"B%5E1=B=%28matrix%282%2C2%2C2%2C1%2C3%2C2%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "iii)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "First, let's calculate \"C%5ET\" (the transpose of matrix C). So simply swap each row and column to get:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So \"C%5ET=%28matrix%282%2C3%2C1%2C3%2C-2%2C4%2C-1%2C5%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now let's multiply the matrices B and \"C%5ET\":\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the first matrix is a 2 by 2 matrix and the second matrix is a 2 by 3 matrix, this means that the resulting matrix will be a 2 by 3 matrix.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the final resulting matrix will look like:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2Cx%2Cx%2Cx%2Cx%2Cx%2Cx%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "note: the \"x\"s are just placeholders for now\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 1st row of the first matrix by the 1st column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "1st row, 1st column: \r
\n" ); document.write( "\n" ); document.write( "\"%282%29%2A%281%29%2B%281%29%2A%284%29=2%2B4=6\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 1st row, 1st column of the resulting matrix is \"6\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C6%2Cx%2Cx%2Cx%2Cx%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 1st row of the first matrix by the 2nd column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "1st row, 2nd column: \r
\n" ); document.write( "\n" ); document.write( "\"%282%29%2A%283%29%2B%281%29%2A%28-1%29=6%2B-1=5\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 1st row, 2nd column of the resulting matrix is \"5\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C6%2C5%2Cx%2Cx%2Cx%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 1st row of the first matrix by the 3rd column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "1st row, 3rd column: \r
\n" ); document.write( "\n" ); document.write( "\"%282%29%2A%28-2%29%2B%281%29%2A%285%29=-4%2B5=1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 1st row, 3rd column of the resulting matrix is \"1\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C6%2C5%2C1%2Cx%2Cx%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "================================================================================\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 2nd row of the first matrix by the 1st column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "2nd row, 1st column: \r
\n" ); document.write( "\n" ); document.write( "\"%283%29%2A%281%29%2B%282%29%2A%284%29=3%2B8=11\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 2nd row, 1st column of the resulting matrix is \"11\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C6%2C5%2C1%2C11%2Cx%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 2nd row of the first matrix by the 2nd column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "2nd row, 2nd column: \r
\n" ); document.write( "\n" ); document.write( "\"%283%29%2A%283%29%2B%282%29%2A%28-1%29=9%2B-2=7\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 2nd row, 2nd column of the resulting matrix is \"7\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C6%2C5%2C1%2C11%2C7%2Cx%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Multiply the corresponding entries from the 2nd row of the first matrix by the 3rd column of the second matrix. After multiplying, add the values:\r
\n" ); document.write( "\n" ); document.write( "2nd row, 3rd column: \r
\n" ); document.write( "\n" ); document.write( "\"%283%29%2A%28-2%29%2B%282%29%2A%285%29=-6%2B10=4\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " So the element in the 2nd row, 3rd column of the resulting matrix is \"4\". Now let's update the matrix:\r
\n" ); document.write( "\n" ); document.write( " \r
\n" ); document.write( "\n" ); document.write( "\"%28matrix%282%2C2%2C6%2C5%2C1%2C11%2C7%2C4%29%29\"\r
\n" ); document.write( "\n" ); document.write( "--------------------------------------------------\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "==============================================================================\r
\n" ); document.write( "
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\n" ); document.write( "\n" ); document.write( "Answer:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the solution is \"%28matrix%282%2C3%2C6%2C5%2C1%2C11%2C7%2C4%29%29\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "In other words,\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "which in short means \"BC%5ET=%28matrix%282%2C3%2C6%2C5%2C1%2C11%2C7%2C4%29%29\"
\n" ); document.write( "
\n" );