- #1
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Another vent of frustration:
I hereby nominate the three worst offences committed in maths textbooks as
0. Elementary textbooks asserting a 'fact' that is clearly wrong and going to lead to confusion at a later date. Example: you cannot square root negative numbers. It takes a huge amount of effort to de-program students who have very fixed ideas when they come to university (since complex numbers are even less likely to be taught at high-school anymore).
1. Using an equals sign when you do not mean equals. Example: an A-level textbook I taught from asserted that the square root of 2 _equalled_ 1.41
2. Asking what the domain of, say, [itex]\sqrt{x^2-4}[/itex] is. The domain is part of the definition of a function - that is just an expression at best. See offence 0. Does it suddenly become a function when you learn about complex numbers?
Feel free to add your own.
I hereby nominate the three worst offences committed in maths textbooks as
0. Elementary textbooks asserting a 'fact' that is clearly wrong and going to lead to confusion at a later date. Example: you cannot square root negative numbers. It takes a huge amount of effort to de-program students who have very fixed ideas when they come to university (since complex numbers are even less likely to be taught at high-school anymore).
1. Using an equals sign when you do not mean equals. Example: an A-level textbook I taught from asserted that the square root of 2 _equalled_ 1.41
2. Asking what the domain of, say, [itex]\sqrt{x^2-4}[/itex] is. The domain is part of the definition of a function - that is just an expression at best. See offence 0. Does it suddenly become a function when you learn about complex numbers?
Feel free to add your own.