history of mathematics - National STEM Centre
history of mathematics - National STEM Centre
history of mathematics - National STEM Centre
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754<br />
12 Summaries and exercises<br />
5 Arab <strong>mathematics</strong><br />
Chapter summary<br />
• some inheritance problems from Islamic law (Activity 5.1).<br />
• how Arabic work on trigonometry built on the work <strong>of</strong> Ptolemy to compile<br />
trigonometric tables (Activities 5.2 and 5.3)<br />
• examples <strong>of</strong> problems from the East worked on by Arab mathematicians<br />
(Activity 5.4)<br />
• how Thabit ibn Qurra investigated amicable numbers (Activity 5.5)<br />
• some Chinese methods for solving equations which were available to the Arabs<br />
(Activities 5.6 and 5.7)<br />
• the origins <strong>of</strong> the word 'algebra' (text before Activity 5.8)<br />
• the six types <strong>of</strong> quadratic equation solved algorithmically, with geometric<br />
justification, by al-Khwarizmi (text and Activity 5.8)<br />
• some <strong>of</strong> the 19 types <strong>of</strong> cubic solved by Omar Khayyam (text and Activity 5.9)<br />
• methods for finding local maxima and minima to help find the solutions <strong>of</strong> a<br />
cubic (Activity 5.10).<br />
Practice exercises<br />
1 A particular equation which was considered by al-Khwarizmi can be translated<br />
as follows.<br />
I one square and ten roots <strong>of</strong> the same equal thirty-nine.<br />
a Express this equation in a modern algebraic form.<br />
b Draw a square ABCD with side AB representing the 'root' <strong>of</strong> the equation.<br />
Extend AB to E and AD to F where BE = DF = 5, and complete the larger square<br />
on side AE. Extend the lines BC and DC to meet the larger square. Shade the areas<br />
representing the 'one square and ten roots <strong>of</strong> the same' in al-Khwarizmi's problem.<br />
c Hence find the positive solution to the equation.<br />
2 Explain why al-Khwarizmi's classification <strong>of</strong> quadratic equations does not<br />
include the case or cases in which squares and roots and numbers equal zero.<br />
3 Which <strong>of</strong> the Arabic numerals look most like those used in English texts today?<br />
What advantages and disadvantages can you see in the Arabic versions?<br />
4 Use al-Khwarizmi's method to solve x 2 + I2x = 64.<br />
5 Use Homer's method to solve x 2 + Ix = 60750.<br />
6 Write brief notes on Omar Khayyam's contribution to <strong>mathematics</strong>.<br />
7 Draw on your studies <strong>of</strong> Babylonian and Arab <strong>mathematics</strong> to write an account<br />
<strong>of</strong> two different approaches to problems which lead to quadratic equations.<br />
6 The approach <strong>of</strong> Descartes<br />
Chapter summary<br />
• a review <strong>of</strong> the legacy <strong>of</strong> Greek geometrical methods (Activities 6.2 and 6.3)