{"id":998,"date":"2026-01-04T21:55:25","date_gmt":"2026-01-04T11:55:25","guid":{"rendered":"https:\/\/archive4ones.com\/2ndstudy\/?p=998"},"modified":"2026-01-08T23:04:39","modified_gmt":"2026-01-08T13:04:39","slug":"year11-math-2-2-5-warm-up-questions-algebra-and-matrices-the-logic-of-arrays","status":"publish","type":"post","link":"https:\/\/archive4ones.com\/2ndstudy\/?p=998","title":{"rendered":"Year11 MATH 2-2-5 Warm-up Questions-Algebra and Matrices (The Logic of Arrays)"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">In Chapter 5 of General Mathematics, we step into the world of <strong>Matrices<\/strong>. These are not just boxes of numbers; they are powerful tools for organizing data, solving systems of equations, and analyzing complex networks. Mastering the &#8220;Logic of Arrays&#8221; allows you to process large amounts of information simultaneously\u2014a skill essential for computer science, economics, and engineering.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\"><strong>Concepts and Skills Covered:<\/strong><\/h3>\n\n\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Matrix Notation:<\/strong> Identifying the order (rows <math data-latex=\"\\times\"><semantics><mo lspace=\"0em\" rspace=\"0em\">\u00d7<\/mo><annotation encoding=\"application\/x-tex\">\\times<\/annotation><\/semantics><\/math> columns) and specific elements (<math data-latex=\"a_{ij}\"><semantics><msub><mi>a<\/mi><mrow><mi>i<\/mi><mi>j<\/mi><\/mrow><\/msub><annotation encoding=\"application\/x-tex\">a_{ij}<\/annotation><\/semantics><\/math>).<\/li>\n\n\n\n<li><strong>Arithmetic Operations:<\/strong> Performing addition, subtraction, and scalar multiplication.<\/li>\n\n\n\n<li><strong>Matrix Multiplication:<\/strong> Understanding conformability and the row-by-column multiplication process.<\/li>\n\n\n\n<li><strong>Special Matrices:<\/strong> Utilizing Identity (<math data-latex=\"I\"><semantics><mi>I<\/mi><annotation encoding=\"application\/x-tex\">I<\/annotation><\/semantics><\/math>) and Zero (<math data-latex=\"O\"><semantics><mi>O<\/mi><annotation encoding=\"application\/x-tex\">O<\/annotation><\/semantics><\/math>) matrices.<\/li>\n\n\n\n<li><math data-latex=\"2 \\times 2\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>2<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 2<\/annotation><\/semantics><\/math><strong> Determinants and Inverses:<\/strong> Calculating the determinant (<math data-latex=\"ad - bc\"><semantics><mrow><mi>a<\/mi><mi>d<\/mi><mo>\u2212<\/mo><mi>b<\/mi><mi>c<\/mi><\/mrow><annotation encoding=\"application\/x-tex\">ad &#8211; bc<\/annotation><\/semantics><\/math>) and finding the inverse to solve equations.<strong>Network Analysis:<\/strong> Representing connections as adjacency matrices and using powers of matrices (like <math data-latex=\"A^2\"><semantics><msup><mi>A<\/mi><mn>2<\/mn><\/msup><annotation encoding=\"application\/x-tex\">A^2<\/annotation><\/semantics><\/math>) to find multi-step paths.<\/li>\n<\/ol>\n\n\n\n<p class=\"wp-block-paragraph\">***************************<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q1<\/strong>. What is the order (dimensions) of the matrix <math data-latex=\"A = \\begin{pmatrix} 4 &amp; -1 &amp; 0 \\\\ 2 &amp; 5 &amp; 8 \\end{pmatrix}\"><semantics><mrow><mi>A<\/mi><mo>=<\/mo><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>4<\/mn><\/mtd><mtd><mrow><mo>\u2212<\/mo><mn>1<\/mn><\/mrow><\/mtd><mtd style=\"padding-right:0em;\"><mn>0<\/mn><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>2<\/mn><\/mtd><mtd><mn>5<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>8<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><\/mrow><annotation encoding=\"application\/x-tex\">A = \\begin{pmatrix} 4 &amp; -1 &amp; 0 \\\\ 2 &amp; 5 &amp; 8 \\end{pmatrix}<\/annotation><\/semantics><\/math>?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. 6<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B. 2\u00d73<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C. 1\u00d76<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D. 3\u00d72<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: Count the number of horizontal rows first, then the number of vertical columns.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q2.<\/strong> Under what condition can two matrices, <math data-latex=\"A\"><semantics><mi>A<\/mi><annotation encoding=\"application\/x-tex\">A<\/annotation><\/semantics><\/math> and <math data-latex=\"B\"><semantics><mi>B<\/mi><annotation encoding=\"application\/x-tex\">B<\/annotation><\/semantics><\/math>, be added or subtracted?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. They must have the exact same order (dimensions).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B. The determinant of both matrices must be non-zero.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C. The number of columns in <em>A<\/em> must equal the number of rows in <em>B<\/em>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D. They must both be square matrices.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: Think about whether you could add a <math data-latex=\"2 \\times 2\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>2<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 2<\/annotation><\/semantics><\/math> matrix to a <math data-latex=\"3 \\times 3\"><semantics><mrow><mn>3<\/mn><mo>\u00d7<\/mo><mn>3<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">3 \\times 3<\/annotation><\/semantics><\/math> matrix.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q3.<\/strong> If <math data-latex=\"B = \\begin{pmatrix} 3 &amp; -2 \\\\ 1 &amp; 4 \\end{pmatrix}\"><semantics><mrow><mi>B<\/mi><mo>=<\/mo><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>3<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mrow><mo>\u2212<\/mo><mn>2<\/mn><\/mrow><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>1<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>4<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><\/mrow><annotation encoding=\"application\/x-tex\">B = \\begin{pmatrix} 3 &amp; -2 \\\\ 1 &amp; 4 \\end{pmatrix}<\/annotation><\/semantics><\/math>, what is the result of the scalar multiplication 3<em>B<\/em>?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. <math data-latex=\"\\begin{pmatrix} 9 &amp; -2 \\\\ 1 &amp; 4 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>9<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mrow><mo>\u2212<\/mo><mn>2<\/mn><\/mrow><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>1<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>4<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 9 &amp; -2 \\\\ 1 &amp; 4 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B. <math data-latex=\"\\begin{pmatrix} 27 &amp; -18 \\\\ 9 &amp; 36 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>27<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mrow><mo>\u2212<\/mo><mn>18<\/mn><\/mrow><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>9<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>36<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 27 &amp; -18 \\\\ 9 &amp; 36 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C. <math data-latex=\"\\begin{pmatrix} 9 &amp; -6 \\\\ 3 &amp; 12 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>9<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mrow><mo>\u2212<\/mo><mn>6<\/mn><\/mrow><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>3<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>12<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 9 &amp; -6 \\\\ 3 &amp; 12 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D. <math data-latex=\"\\begin{pmatrix} 6 &amp; 1 \\\\ 4 &amp; 7 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>6<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>1<\/mn><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>4<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>7<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 6 &amp; 1 \\\\ 4 &amp; 7 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: Distribute the number 3 to every number inside the brackets.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q4. <\/strong>Matrix <math data-latex=\"M\"><semantics><mi>M<\/mi><annotation encoding=\"application\/x-tex\">M<\/annotation><\/semantics><\/math> has order <math data-latex=\"3 \\times 2\"><semantics><mrow><mn>3<\/mn><mo>\u00d7<\/mo><mn>2<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">3 \\times 2<\/annotation><\/semantics><\/math> and Matrix <math data-latex=\"N\"><semantics><mi>N<\/mi><annotation encoding=\"application\/x-tex\">N<\/annotation><\/semantics><\/math> has order <math data-latex=\"2 \\times 5\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>5<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 5<\/annotation><\/semantics><\/math>. What is the order of the resulting matrix <math data-latex=\"MN\"><semantics><mrow><mi>M<\/mi><mi>N<\/mi><\/mrow><annotation encoding=\"application\/x-tex\">MN<\/annotation><\/semantics><\/math>?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A.  The multiplication is not possible.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B.  5\u00d73<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C.  2\u00d72<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D.  3\u00d75<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: The &#8216;inner&#8217; numbers must be the same to multiply, while the &#8216;outer&#8217; numbers determine the new shape.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q5.<\/strong> Given <math data-latex=\"A = \\begin{pmatrix} 1 &amp; 2 \\end{pmatrix}\"><semantics><mrow><mi>A<\/mi><mo>=<\/mo><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>1<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>2<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><\/mrow><annotation encoding=\"application\/x-tex\">A = \\begin{pmatrix} 1 &amp; 2 \\end{pmatrix}<\/annotation><\/semantics><\/math> and <math data-latex=\"B = \\begin{pmatrix} 3 \\\\ 4 \\end{pmatrix}\"><semantics><mrow><mi>B<\/mi><mo>=<\/mo><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center\"><mtr><mtd style=\"padding-left:0em;padding-right:0em;\"><mn>3<\/mn><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;padding-right:0em;\"><mn>4<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><\/mrow><annotation encoding=\"application\/x-tex\">B = \\begin{pmatrix} 3 \\\\ 4 \\end{pmatrix}<\/annotation><\/semantics><\/math>, calculate the product <math data-latex=\"AB\"><semantics><mrow><mi>A<\/mi><mi>B<\/mi><\/mrow><annotation encoding=\"application\/x-tex\">AB<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A.  <math data-latex=\"\\begin{pmatrix} 7 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center\"><mtr><mtd style=\"padding-left:0em;padding-right:0em;\"><mn>7<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 7 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B.   <math data-latex=\"\\begin{pmatrix} 3 &amp; 8 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>3<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>8<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 3 &amp; 8 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C.  <math data-latex=\"\\begin{pmatrix} 11 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center\"><mtr><mtd style=\"padding-left:0em;padding-right:0em;\"><mn>11<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 11 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D.  <math data-latex=\"\\begin{pmatrix} 3 &amp; 4 \\\\ 6 &amp; 8 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>3<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>4<\/mn><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>6<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>8<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 3 &amp; 4 \\\\ 6 &amp; 8 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: Multiply the row elements by the column elements and add them together.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q6.<\/strong> What is the result when any square matrix <math data-latex=\"A\"><semantics><mi>A<\/mi><annotation encoding=\"application\/x-tex\">A<\/annotation><\/semantics><\/math> is multiplied by the identity matrix <math data-latex=\"I\"><semantics><mi>I<\/mi><annotation encoding=\"application\/x-tex\">I<\/annotation><\/semantics><\/math> of the same order?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. Matrix <math data-latex=\"A\"><semantics><mi>A<\/mi><annotation encoding=\"application\/x-tex\">A<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B.  The Inverse matrix <math data-latex=\"A^{-1}\"><semantics><msup><mi>A<\/mi><mrow><mo lspace=\"0em\" rspace=\"0em\">\u2212<\/mo><mn>1<\/mn><\/mrow><\/msup><annotation encoding=\"application\/x-tex\">A^{-1}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C.  The Identity matrix<math data-latex=\"I\"><semantics><mi>I<\/mi><annotation encoding=\"application\/x-tex\">I<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D.  The Zero matrix <em>O<\/em><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint:  Consider the property of the &#8216;identity&#8217; in regular arithmetic (e.g., <math data-latex=\"5 \\times 1\"><semantics><mrow><mn>5<\/mn><mo>\u00d7<\/mo><mn>1<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">5 \\times 1<\/annotation><\/semantics><\/math>).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q7.<\/strong> Calculate the determinant of the matrix <math data-latex=\"C = \\begin{pmatrix} 5 &amp; 2 \\\\ 3 &amp; 4 \\end{pmatrix}\"><semantics><mrow><mi>C<\/mi><mo>=<\/mo><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>5<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>2<\/mn><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>3<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>4<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><\/mrow><annotation encoding=\"application\/x-tex\">C = \\begin{pmatrix} 5 &amp; 2 \\\\ 3 &amp; 4 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. 7<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B. 14<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C. \u221214<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D. 26<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: Subtract the product of the &#8216;off-diagonal&#8217; from the product of the &#8216;main diagonal&#8217;.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q8. <\/strong>A <math data-latex=\"2 \\times 2\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>2<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 2<\/annotation><\/semantics><\/math> matrix is said to be &#8216;singular&#8217; (having no inverse) if:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. All of its elements are positive.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B. It contains at least one zero element.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C. Its determinant is equal to zero.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D. It is not a square matrix.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint:  Think about why you cannot divide by zero in the inverse formula.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q9.<\/strong> In an adjacency matrix representing a network, what does the entry in row <math data-latex=\"i\"><semantics><mi>i<\/mi><annotation encoding=\"application\/x-tex\">i<\/annotation><\/semantics><\/math>, column <math data-latex=\"j\"><semantics><mi>j<\/mi><annotation encoding=\"application\/x-tex\">j<\/annotation><\/semantics><\/math> typically represent?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A. The number of two-step paths between the vertices.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B. The number of direct paths (one-step) from vertex <em>i<\/em> to vertex <em>j<\/em>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C. The importance or &#8216;weight&#8217; of the vertex.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D. The total distance between vertex <em>i<\/em> and vertex <em>j<\/em>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: An adjacency matrix is a map of &#8216;who is connected to whom&#8217;.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q10.<\/strong> If <math data-latex=\"A\"><semantics><mi>A<\/mi><annotation encoding=\"application\/x-tex\">A<\/annotation><\/semantics><\/math> is an adjacency matrix for a communication network, what information does the matrix <math data-latex=\"A^2\"><semantics><msup><mi>A<\/mi><mn>2<\/mn><\/msup><annotation encoding=\"application\/x-tex\">A^2<\/annotation><\/semantics><\/math> provide?<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A.    A list of vertices that are not connected to any others.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">B.   The square of every individual number in the original matrix.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">C.   The number of 2-step paths between any two vertices.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">D.  The network with all connection directions reversed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Hint: Think about what happens to &#8216;steps&#8217; in a path when you multiply the connection matrix by itself.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">*********<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u4e00\u822c\u6570\u5b66\u306e\u7b2c5\u7ae0\u3067\u306f\u3001\u884c\u5217\u306e\u4e16\u754c\u306b\u89e6\u308c\u307e\u3059\u3002\u884c\u5217\u306f\u5358\u306a\u308b\u6570\u5b57\u306e\u7bb1\u3067\u306f\u3042\u308a\u307e\u305b\u3093\u3002\u30c7\u30fc\u30bf\u306e\u6574\u7406\u3001\u9023\u7acb\u65b9\u7a0b\u5f0f\u306e\u89e3\u6cd5\u3001\u8907\u96d1\u306a\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u306e\u89e3\u6790\u306b\u5f79\u7acb\u3064\u5f37\u529b\u306a\u30c4\u30fc\u30eb\u3067\u3059\u3002\u300c\u914d\u5217\u306e\u8ad6\u7406\u300d\u3092\u7fd2\u5f97\u3059\u308b\u3053\u3068\u3067\u3001\u5927\u91cf\u306e\u60c5\u5831\u3092\u540c\u6642\u306b\u51e6\u7406\u3067\u304d\u308b\u3088\u3046\u306b\u306a\u308a\u307e\u3059\u3002\u3053\u308c\u306f\u3001\u30b3\u30f3\u30d4\u30e5\u30fc\u30bf\u30b5\u30a4\u30a8\u30f3\u30b9\u3001\u7d4c\u6e08\u5b66\u3001\u5de5\u5b66\u306b\u4e0d\u53ef\u6b20\u306a\u30b9\u30ad\u30eb\u3067\u3059\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u6271\u3046\u6982\u5ff5\u3068\u30b9\u30ad\u30eb\uff1a<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u884c\u5217\u306e\u8868\u8a18\uff1a\u9806\u5e8f\uff08\u884c <math data-latex=\"\\times\"><semantics><mo lspace=\"0em\" rspace=\"0em\">\u00d7<\/mo><annotation encoding=\"application\/x-tex\">\\times<\/annotation><\/semantics><\/math> \u5217\uff09\u3068\u7279\u5b9a\u306e\u8981\u7d20\uff08<math data-latex=\"a_{ij}\"><semantics><msub><mi>a<\/mi><mrow><mi>i<\/mi><mi>j<\/mi><\/mrow><\/msub><annotation encoding=\"application\/x-tex\">a_{ij}<\/annotation><\/semantics><\/math>\uff09\u3092\u8b58\u5225\u3059\u308b\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u7b97\u8853\u6f14\u7b97\uff1a\u52a0\u7b97\u3001\u6e1b\u7b97\u3001\u30b9\u30ab\u30e9\u30fc\u4e57\u7b97\u3092\u5b9f\u884c\u3059\u308b\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u884c\u5217\u306e\u4e57\u7b97\uff1a\u9069\u5408\u6027\u3068\u884c\u3068\u5217\u306e\u4e57\u7b97\u30d7\u30ed\u30bb\u30b9\u3092\u7406\u89e3\u3059\u308b\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u7279\u6b8a\u884c\u5217\uff1a\u5358\u4f4d\u884c\u5217\uff08<math data-latex=\"I\"><semantics><mi>I<\/mi><annotation encoding=\"application\/x-tex\">I<\/annotation><\/semantics><\/math>\uff09\u3068\u96f6\u884c\u5217\uff08<math data-latex=\"O\"><semantics><mi>O<\/mi><annotation encoding=\"application\/x-tex\">O<\/annotation><\/semantics><\/math>\uff09\u3092\u6d3b\u7528\u3059\u308b\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><math data-latex=\"2 \\times 2\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>2<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 2<\/annotation><\/semantics><\/math> \u884c\u5217\u5f0f\u3068\u9006\u884c\u5217\uff1a\u65b9\u7a0b\u5f0f\u3092\u89e3\u304f\u305f\u3081\u306b\u884c\u5217\u5f0f (<math data-latex=\"ad - bc\"><semantics><mrow><mi>a<\/mi><mi>d<\/mi><mo>\u2212<\/mo><mi>b<\/mi><mi>c<\/mi><\/mrow><annotation encoding=\"application\/x-tex\">ad &#8211; bc<\/annotation><\/semantics><\/math>) \u3092\u8a08\u7b97\u3057\u3001\u9006\u884c\u5217\u3092\u6c42\u3081\u308b\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">\u30cd\u30c3\u30c8\u30ef\u30fc\u30af\u5206\u6790\uff1a\u63a5\u7d9a\u3092\u96a3\u63a5\u884c\u5217\u3068\u3057\u3066\u8868\u73fe\u3057\u3001\u884c\u5217\u306e\u3079\u304d\u4e57\uff08<math data-latex=\"A^2\"><semantics><msup><mi>A<\/mi><mn>2<\/mn><\/msup><annotation encoding=\"application\/x-tex\">A^2<\/annotation><\/semantics><\/math> \u306a\u3069\uff09\u3092\u7528\u3044\u3066\u591a\u6bb5\u968e\u7d4c\u8def\u3092\u6c42\u3081\u308b\u3002<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">**************************<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Right answers.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q1<\/strong>. B. <math data-latex=\"2 \\times 3\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>3<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 3<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The order is written as rows <math data-latex=\"\\times\"><semantics><mo lspace=\"0em\" rspace=\"0em\">\u00d7<\/mo><annotation encoding=\"application\/x-tex\">\\times<\/annotation><\/semantics><\/math> columns; this matrix has 2 horizontal rows and 3 vertical columns.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q2.<\/strong> A. They must have the exact same order (dimensions).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Matrix addition is performed element-by-element, so the positions must correspond exactly in both matrices.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q3.<\/strong> C. <math data-latex=\"\\begin{pmatrix} 9 &amp; -6 \\\\ 3 &amp; 12 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center center\"><mtr><mtd style=\"padding-left:0em;\"><mn>9<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mrow><mo>\u2212<\/mo><mn>6<\/mn><\/mrow><\/mtd><\/mtr><mtr><mtd style=\"padding-left:0em;\"><mn>3<\/mn><\/mtd><mtd style=\"padding-right:0em;\"><mn>12<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 9 &amp; -6 \\\\ 3 &amp; 12 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Scalar multiplication involves multiplying every individual element inside the matrix by the constant 3.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q4.<\/strong> D. <math data-latex=\"3 \\times 5\"><semantics><mrow><mn>3<\/mn><mo>\u00d7<\/mo><mn>5<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">3 \\times 5<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The inner dimensions (2) match for multiplication, and the outer dimensions (3 and 5) define the size of the result.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q5.<\/strong> C. <math data-latex=\"\\begin{pmatrix} 11 \\end{pmatrix}\"><semantics><mrow><mo fence=\"true\" form=\"prefix\">(<\/mo><mtable columnalign=\"center\"><mtr><mtd style=\"padding-left:0em;padding-right:0em;\"><mn>11<\/mn><\/mtd><\/mtr><\/mtable><mo fence=\"true\" form=\"postfix\">)<\/mo><\/mrow><annotation encoding=\"application\/x-tex\">\\begin{pmatrix} 11 \\end{pmatrix}<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Multiplying a <math data-latex=\"1 \\times 2\"><semantics><mrow><mn>1<\/mn><mo>\u00d7<\/mo><mn>2<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">1 \\times 2<\/annotation><\/semantics><\/math> by a <math data-latex=\"2 \\times 1\"><semantics><mrow><mn>2<\/mn><mo>\u00d7<\/mo><mn>1<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">2 \\times 1<\/annotation><\/semantics><\/math> gives a <math data-latex=\"1 \\times 1\"><semantics><mrow><mn>1<\/mn><mo>\u00d7<\/mo><mn>1<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">1 \\times 1<\/annotation><\/semantics><\/math> result: <math data-latex=\"(1 \\times 3) + (2 \\times 4) = 3 + 8 = 11\"><semantics><mrow><mo form=\"prefix\" stretchy=\"false\">(<\/mo><mn>1<\/mn><mo>\u00d7<\/mo><mn>3<\/mn><mo form=\"postfix\" stretchy=\"false\">)<\/mo><mo>+<\/mo><mo form=\"prefix\" stretchy=\"false\">(<\/mo><mn>2<\/mn><mo>\u00d7<\/mo><mn>4<\/mn><mo form=\"postfix\" stretchy=\"false\">)<\/mo><mo>=<\/mo><mn>3<\/mn><mo>+<\/mo><mn>8<\/mn><mo>=<\/mo><mn>11<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">(1 \\times 3) + (2 \\times 4) = 3 + 8 = 11<\/annotation><\/semantics><\/math>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q6.<\/strong> A. Matrix <math data-latex=\"A\"><semantics><mi>A<\/mi><annotation encoding=\"application\/x-tex\">A<\/annotation><\/semantics><\/math><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The identity matrix acts like the number 1 in scalar multiplication; it leaves the original matrix unchanged (<math data-latex=\"AI = IA = A\"><semantics><mrow><mi>A<\/mi><mi>I<\/mi><mo>=<\/mo><mi>I<\/mi><mi>A<\/mi><mo>=<\/mo><mi>A<\/mi><\/mrow><annotation encoding=\"application\/x-tex\">AI = IA = A<\/annotation><\/semantics><\/math>).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q7.<\/strong> B. 14<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The determinant is calculated as <math data-latex=\"ad - bc\"><semantics><mrow><mi>a<\/mi><mi>d<\/mi><mo>\u2212<\/mo><mi>b<\/mi><mi>c<\/mi><\/mrow><annotation encoding=\"application\/x-tex\">ad &#8211; bc<\/annotation><\/semantics><\/math>, which is <math data-latex=\"(5 \\times 4) - (2 \\times 3) = 20 - 6 = 14\"><semantics><mrow><mo form=\"prefix\" stretchy=\"false\">(<\/mo><mn>5<\/mn><mo>\u00d7<\/mo><mn>4<\/mn><mo form=\"postfix\" stretchy=\"false\">)<\/mo><mo>\u2212<\/mo><mo form=\"prefix\" stretchy=\"false\">(<\/mo><mn>2<\/mn><mo>\u00d7<\/mo><mn>3<\/mn><mo form=\"postfix\" stretchy=\"false\">)<\/mo><mo>=<\/mo><mn>20<\/mn><mo>\u2212<\/mo><mn>6<\/mn><mo>=<\/mo><mn>14<\/mn><\/mrow><annotation encoding=\"application\/x-tex\">(5 \\times 4) &#8211; (2 \\times 3) = 20 &#8211; 6 = 14<\/annotation><\/semantics><\/math>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q8.<\/strong> C. Its determinant is equal to zero.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Since the formula for the inverse involves dividing by the determinant, a zero value makes the calculation undefined.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q9.<\/strong> B. The number of direct paths (one-step) from vertex <math data-latex=\"i\"><semantics><mi>i<\/mi><annotation encoding=\"application\/x-tex\">i<\/annotation><\/semantics><\/math> to vertex <math data-latex=\"j\"><semantics><mi>j<\/mi><annotation encoding=\"application\/x-tex\">j<\/annotation><\/semantics><\/math>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Adjacency matrices record the immediate connections between nodes in a graph or network.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Q10.<\/strong> C. The number of 2-step paths between any two vertices.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Raising the adjacency matrix to the power of <math data-latex=\"n\"><semantics><mi>n<\/mi><annotation encoding=\"application\/x-tex\">n<\/annotation><\/semantics><\/math> reveals the number of <math data-latex=\"n\"><semantics><mi>n<\/mi><annotation encoding=\"application\/x-tex\">n<\/annotation><\/semantics><\/math>-step paths available in the network.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><\/p>\n","protected":false},"excerpt":{"rendered":"<p>In Chapter 5 of General Mathematics, we step into the world of Matrices. These are not just boxes of numbers; they are powerful tools for organizing data, solving systems of equations, and analyzing complex networks. Mastering the &#8220;Logic of Arrays&#8221; allows you to process large amounts of information simultaneously\u2014a skill essential for computer science, economics, [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-998","post","type-post","status-publish","format-standard","hentry","category-math"],"_links":{"self":[{"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=\/wp\/v2\/posts\/998","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=998"}],"version-history":[{"count":6,"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=\/wp\/v2\/posts\/998\/revisions"}],"predecessor-version":[{"id":1019,"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=\/wp\/v2\/posts\/998\/revisions\/1019"}],"wp:attachment":[{"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=998"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=998"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/archive4ones.com\/2ndstudy\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=998"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}