CRAMERS RULE

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• CRAMERS RULE
• Reference Croft Davision, Chapter 8, Blocks
  1, 2
• http//www.math.utep.edu/sos/math
• Cramers Rule
• Cramers rule is a method that uses determinants
  to solve a system of linear equations.
• i. 2 equations, 2 unknowns
• If

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then ii. 3 equations, 3 unknowns if
then
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e.g. 1 Using Cramers rule, solve for x, y.
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e.g. 2 Using Cramers rule, solve for x, y and
z.
Exercise p.431 Q1a, 1b, 2a, 2d
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Writing system of Equations in Matrix Form Note
that can be written as This is called the matrix
form of the simultaneous equations.
Similarly, can also be written as
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i.e. the general matrix form of a system of
equations where A, X and B are matrices.
AX B
Solving Equations using the Inverse Matrix
Method Consider the matrix form AX
B A-1AX A-1 B I X A-1 B X A-1
B i.e. X can be found if A-1 exists.
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e.g.3 Redo example1 and example2 using the
inverse matrix method.
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Exercise p.439, End of block exercise, Q1a, 2, 3