7th of March, 2014 (Friday)

Page 48

Comments (5)

5th of December, 2014 (Friday)
Eirika R.
I just noticed the little note Ash made... the way I was taught Algebra was just to write a regular X, and the multiplication symbol was a dot. Is it (the X that looks like two c's back to back, with a regular multiplication symbol) an Australian thing, or just how Ash writes things? (sorry if I'm a little ignorant...)
I think the curly x is something I picked up from my high school teacher. Usually we don't use any symbol and write the two variables one after the other to say multiplication. But if it's two numbers you can't do that, so an x is used.
This is probably different depending on the state, though.
24th of March, 2015 (Tuesday)
Correctly done, algebra uses · for multiplication. The slightly curvy X is just a handwriting pique. Mine do that too, and I'm not Australian at all. Tober is right in that with variables, it's normally skipped unless there is some specific reason for using it, to prevent confusion with scalar dot products (which have specific rules about inputs). As a result, "x·y", "xy", and "(x)(y)" are all equivalent expressions. Likewise, "3·6", "(3)(6)", and "18" are also all equivalent expressions. Not that in "3·6", you have a specific reason for writing the symbol explicitly, since if you leave it out you have 36 instead of 18.
28th of May, 2016 (Saturday)
I tutored a kid once a week for a year; it took rather a few months for the idea of algebra to start sinking in.
15th of July, 2017 (Saturday)
The problem here is in handwriting differentiating between "." And" ·". Three and a half, "3.5" can easily look like "3·5" three multiplied by 5. We were told the correct way though the teacher insisted on the incorrect though clearer use of the two types of X.

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