Thread: 6÷2(1+2) = ? View Single Post
April 28th, 2011, 08:41 PM   #51 (permalink)
EarlyMon
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Quote:
 Originally Posted by sonofaresiii Well I disagree with your disagreement! So there! edit: to explain myself a little better, no, i'm not saying f(x) = 2*x. In fact, I'm saying that's the problem-- OTHER people are saying that, but it's not true. f(x) is a function, that is f of x (f is a function of x), meaning the variable f is applied to the variable x. In our equation, we would apply 2 to 3, which in effect is multiplying it... but it's not the same as saying f(x) = f*x (though isolated, those equations are redundant). The problem is that USUALLY creating a function simply means multiplying it, so we've been trained to think that 2(3) = 2*3. But it isn't.
Um. f(x) is literally function of x - and does not mean the variable f is applied to x.

How about functions of the form -

where the last sum is simply the first sum rewritten using the definitions ξn = n/T, and Δξ = (n + 1)/Tn/T = 1/T.
Quote:
 f(x) is a function, that is f of x (f is a function of x), meaning the variable f is applied to the variable x.
No. In the above example, there is no variable f that is applied to variable x.

The f in f(x) is simply a placeholder - for the operations that are applied to x.

Quote:
 we've been trained to think that 2(3) = 2*3. But it isn't.
We've been trained to think that way for a reason. Commutation - it comes from commutation notation and means 2*3.

Honest.

So, by direct evaluation, the equation must become 6/2*3 - as had been said before.

 Last edited by EarlyMon; April 28th, 2011 at 08:45 PM.
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