Sunday, December 11, 2011

Determinants!

~Notation- | |similar to absolute value

~If the determinant =0 then it is called a singular matrix because it doesn't have an inverse.

~For a 2X2 matrix you use ad-bc

~For a 3X3 matrix - recopy the first 2 columns, then multiply the diagonals add the right, subtract the left

~For a 4X4 matrix it may be easier to just use your calculator.
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Ex.1:
find the determinant of:
|2 6|
|1 9|
2(9)-6(1)=12

Ex.2:
find the determinant of:
|5 6 4|
|0 4 7|=-162
|3 8 2|

Ex.3:
find the determinant of:
|1 9 6 4|
|2 5 4 3|=-123
|7 0 8 6|
|5 2 9 8|

Ex.4:
find the determinant of:
|12 3|=174
|2 15|

Ex.5:
find the determinant of:
|2 13 8|
|11 6 3|=-963
|7 5 10|

Ex.6:
find the determinant of:
|0 1 2 3|
|2 0 1 4|=25
|6 2 3 1|
|1 0 0 3|

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