And that is how I can tell you are just a poser, and don't actually know squat. You read it incorrectly, and if you knew the topic you wouldn't have done so. You weren't taught that basic arithmetic equations are called identities. |
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I'm not twisting words or anything. I'm not taking it out of context. Learn to read. |
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Previously PhilosopherStoned
And that is how I can tell you are just a poser, and don't actually know squat. You read it incorrectly, and if you knew the topic you wouldn't have done so. You weren't taught that basic arithmetic equations are called identities. |
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Actually, asshole, 4 is a "constant function". That's how it is because it's usual to regard anything as a function so that an equation would be f(x) = g(x) and that would be an identity if f(x) = g(x) for all x. So 2 + 2 would be the constant function 2 added to itself and we have something like f(x) + f(x) = g(x) where f(x) = 2 and g(x) = 4. |
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Previously PhilosopherStoned
You are either trying to be obnoxious, or you are really are totally clueless. I know what functions are, and I know everything you have been talking about on this thread. That is how I know you are totally wrong, and what you are saying doesn't make any sense. |
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LMAO. So cos2(x) + sin2(x) = 1 isn't an identity? Better inform all the trig teachers. It seems pretty specific to me. Or it at least removes the assertion that 2 + 2 = 4 can't be an identity because it's "a specific equation". Not that I think it's an equation but it is by your definition. |
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Previously PhilosopherStoned
That is a trig identity because it works for all numbers. It isn't specific, but extremely general. If x is 5 it works. If x is 7 it works, if its 320, 76, 2, 5.4, 1/2, pi, 1,000, a million, it doesn't matter. That all work. I told you like five times, if something works for all numbers then it is an identity. |
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Last edited by Alric; 03-20-2012 at 08:47 AM.
We're not disagreeing that if something works for all inputs then it's an identity. That's basically the definition of an identity: it's true across it's entire range of input values, i.e. across its whole domain. |
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Previously PhilosopherStoned
punk |
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Previously PhilosopherStoned
Sorry. |
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Previously PhilosopherStoned
Using your logic, all equations(that actually exist as valid equations) are identities and clearly that is incorrect. In fact, that is exactly what you defined an equation as, since no equation would have a number within it's domain that is false. The definition of a domain, is all possible numbers that can be inputed into an equation. If some number is false, it can't be plugged into the equation and thus doesn't exist within it's domain. |
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So what does it mean for a number to be false? Or for a variable to be false? Would you care to clarify? |
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Previously PhilosopherStoned
That it doesn't exist. There are no numbers within a domain that don't exist, because being within the domain implies that it does exist. |
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Also, the rule 2 + 2 = 4 is useful precisely when one has an expression including 2 + 2 that one would like to simplify. Don't let the point that it's trivial fool you. |
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Previously PhilosopherStoned
Go by math.stackexchange.com and ask if 2 + 2 = 4 is an identity. LMAO |
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Previously PhilosopherStoned
The trig identities are useful as a rule because they help in a lot of situations. With 2+2=4 you would never memorize it as a special rule, you would just do the insanely easy addition. |
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So the domain is empty (not "doesn't exist"). Hence the statement 2 + 2 = 4 is true for all elements of its domain vacuously. Like I said, find an element of its domain (either the empty set or any set that you want to define a constant function from) for which it's false. This is vacuous truth and is one of the more basic issue that beginning math students must grapple with. You're sure gung-ho about the virtues of math and logic for someone that doesn't understand it. |
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Previously PhilosopherStoned
You seem to be missing the point. If you make the claim that an identity is an equation where all the values within its domain exist, then by default all equations are then identities because domains are just numbers that exist for the given equation. That is the claim you made, and it is incorrect. |
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I didn't say that all values within the domain exist, I said that it's a mathematical statement which is true for all values within its domain. That's the claim I made and it's correct. |
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Previously PhilosopherStoned
To recap I called an equation, an equation. You insulted me and called me stupid for thinking an equation could actually be called an equation. You admit that it was an equation, but insulted me some more and in an attempt to save face for being wrong you made the claim that a lot of people wouldn't call it an equation. I disagreed, you posted a bunch of crap. I even admitted that it could technically be consider an identity but that is so pointless no one would ever call it such, we argued some more and here we are. |
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That's a bad and biased recap. You called something an equation. I knew it to be an identity. According to the only definition I've actually run across in books (most consider it known) a statement with an equal sign in it is either a definition, an equation, or an identity. But this is already an identity. Hence it can't be an equation. An equation is something one solves. |
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Last edited by PhilosopherStoned; 03-21-2012 at 11:55 PM.
Previously PhilosopherStoned
But okay. For the sake of argument, I'll take your challenge in a colloquial manner and just show you this: banach-tarki. This is a well known result and is known to far more people than can understand even the intuition behind its proof. |
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Previously PhilosopherStoned
Oh yeah, that's just a bunch of crap. |
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Previously PhilosopherStoned
I am not going to get into that debate again, anyone can read the thread and come up with their own conclusion on weather or not normal people call that an equation or not. |
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That isn't just 2+2. You are adding to the equation. |
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