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Algebra
2 Lesson 1
Matrices (Grades 9-12)
Instruction 1-4 What are Matrices | Adding Matrices | Subtracting Matrices | Determinant | Solving Systems of Equations Using Matrices | Summary |
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DETERMINANT
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| Standards: CA: Algebra 2 2.0 NY: Learning Standards for Math Standard 3.0 | ||||
Only square matrices have determinants. Determinant of a
matrix is shown by placing the entries of the matrix between two vertical bars |
|. Determinant of a 2 × 2 Square Matrix
Determinant of a 3 × 3 Square Matrix
det S = 6(3 × 2 – 4 × 8) – 5(1 × 2 – 4 × 7) + 9(1 × 8 – 3 × 7) = 6(6 – 32) – 5(2 – 28) + 9(8 – 21) = 6(–26) – 5(–26) + 9(–13) = –156 + 130 – 117 = –143 Practice 11. Find the determinant of each matrix.
–2[2(11) – 2(0)] – (–3)[–1(11) – 2(–7)] + 3[–1(0) – 2(–7)] = –2(22) + 3(–11 + 14) + 3(14) = –44 + 9 + 42 = 7
(b)
= 1(0) – 10(2) + 100(1) = 0 – 20 + 100 = 80
Video Instruction
Links for Students, Parents and Teachers Now let's do Practice Exercise 1-4 (top). Choose printer friendly or online exercises. Printer friendly version requires the Adobe Acrobat Reader 5. Click HERE to obtain a free copy.
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