Unformatted text preview: Zero • Recall first used as a medial place-holder (but not alone) by Babylonians in 300 BC. • Mayans also had it about 300 BC. • Ptolemy used a genuine zero in 130 AD in a hybrid Greek/Babylonian system. • Brahmagupta in 628 AD used first decimal zero, and this got transmitted to Arabian math- ematicians and subsequently to the West. (Brahmagupta himself was influenced by the Babylonians’ medial zero and Ptolemy’s sexagesimal zero.) Negative Numbers • Hard for us to imagine doing without them, but there is a sense in which it is natural do so. We have been trained to see their usefulness. (Flatland?) • Needed for solving linear equations. • Useful in commerce and were thus used before completely accepted by mathematicians. • Used in first century BC by Chinese. (Before they had zero!) Red and black rods for positive and negative, respectively, (reverse of us) but a rod of length zero easily gets lost....
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- Fall '10
- Complex Numbers, Wallis, Complex number, ﬁrst century BC