MAT 300-02L                         Some Babylonian “Algebra”

Spring 2006

 

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            “Babylonian”                Translation                    Modern algebraic “equivalent    “          

sidi                               side                                          x

 

mehr                             square (or area of square)         x2

 

ush                               length                                       x

 

sag                               breadth                                     y

 

kush                             height                                       z

 

asha                             area                                          xy

 

sahar                            volume                         xyz

 

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Sample problems similar to some Babylonian problems but with “nice” numbers:

 

Suppose that the length and breadth of a rectangle added together is 20 and that twice the length added to five times the breadth is 55.   Multiply 2 times 20; you get 40.  Subtract 40 from 55; you get 15.  Subtract 2 from 5; you get 3.  Divide 15 by 3; you get 5.  Subtract 5 from 20; you get 15.  The length is 15 and the breadth is 5..

 

 

 

 

Suppose two numbers have a sum of 14 and a product of 45.  Find the two numbers.  First, halve 14; you get 7.  Multiply 7 by 7; you get 49.   Subtract 45 from the 49; you get 4.  And 2 is the root.  Add 2 to 7.  Subtract 2 from 7.  One number is 9 and the other is 5.

 

 

 

 

I have added up the area and sixteen sides of my square; 132.  Write down 16, the coefficient.  Break off half of 16; 8.  8 and 8 you multiply; 64.  You add 64 to 132.  The result is 196.  This is the square of 14.  From 14, subtract 8, which you squared above.  6 is the side of the square.

 


The problems below are transcriptions of problems from actual Babylonian tablets.  The translations (which do not include the boldface) are from The History of mathematics : a reader, edited by John Fauvel and Jeremy Gray, published by Basingstoke : Palgrave MacMillan in association with the Open University, 1987.

 

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BM 13901

 

I have added up the area and the side of my square; 0;45.  You write down 1, the coefficient.  You break off half of 1.  0;30 and 0;30 you multiply: 0;15.  You add 0;15 to 0;45: 1.  This is the square of 1.  From 1, you subtract 0;30, which you multiplied.  0;30 is the side of the square.

 

I have subtracted the side of my square from the area: 14,30.  You write down 1, the coefficient.  You break off half of 1.  0;30 and 0;30 you multiply.  You add 0;15 to 14,30.  Result 14,30;15.  This is the square of 29;30.  You add 0;30, which you multiplied to 29:30.  Result 30, the side of the square.

 

I have added up seven times the side of my square and eleven times the area: 6;15.  You write down 7 and 11.  You multiply 6;15 by 11  :   1,8;45.  You break off half of 7.  3;30 and 3;30 you multiply.  12;15 you add to 1,8;45.  Result 1,21.  This is the square of 9.  You subtract 3;30, which you multiplied, from 9.  Result 5;30.  The reciprocal of 11 can not be found.  By what must I multiply 11 to obtain 5;30?  0;30, the side of the square is 0;30.

 

The surfaces of my two square figures I have taken together:  21;15.  The side of one is a seventh less than the other. You write down 7 and 6.  7 and 7 you multiply; 49.  6 and 6 you multiply.  36 and 49 you add:  1;25.  The reciprocal of 1;25 cannot be found.  By what must I multiply 1;25 to give me 21;15?  0;15.  0;30 the side.  0;30 to 7 you raise:  3;30  the first side.  0;30 to 6 you raise:  3 the second side.

 

 

 

YBC 6967

[Two numbers have a product of 1,0]  The larger exceeds the smaller by 7.  What are [the two numbers]?  As for you, halve 7, by which the larger exceeds the smaller, and the result is 3;30.  Multiply together 3;30 with 3;30, and the result is 12;15.  To 12;15, which resulted for you, add 1,0, the product, and the result is 1,12;15.  What is the square root of  1,12;15?  8;30.  Lay down  8;30 and 8;30, its equal, and then subtract 3;30 from the one and add it to the other.  One is 12, the other 5.  [These are the two numbers.]