- #1
dimachka
- 47
- 0
[tex] -1 = \sqrt[3]{-1} = -1 ^ \frac{1}{3} = -1 ^ \frac{2}{6} = ((-1)^2)^\frac{1}{6} = 1^\frac{1}{6} = 1 [/tex]
dimachka said:i would need to explain it using elementary mathematics and elementary concepts because not everybody has a collegiate mathematics education...
nazgjunk said:Well, i still don't really get it. Guess I'll let my maths teacher have a look at it next wednesday, I hope he can explain it to me.
Probably I am just too stubborn too see it, as usual. For some reason I tend to forget what I am doing, and then I don't understand a thing anymore.
dimachka said:I think a better way to explain the problem someone would have understanding this is: "Why must every step in a series of algebraic manipulations be reversible to guarantee that the logic will be sound?"
nazgjunk said:I think i am finally starting to understand this. And as for "Why must every step in a series of algebraic manipulations be reversible to guarantee that the logic will be sound?", no one ever told me that, but it sounds good to me.
dimachka said:I think a better way to explain the problem someone would have understanding this is: "Why must every step in a series of algebraic manipulations be reversible to guarantee that the logic will be sound?"
matt grime said:it is not the algebriac manipulations need to be reverisible, just that each logical step is actually sound to begin with. it so happens that becuase you cannot invert squaring that you have made a logically inconsistent deduction.
matt grime said:the step you claim is logically consistent is: if x^2=y^2 then x=y. now, surely you can see that is false (we even have a counter example that shows this is false). that is what it is saying when we take square roots and think that the answers must be what we started with.
dimachka said:I think it is that each algebraic manipulation must be reversible, i think that is the crux of algebra. In this case, the reason the operation of squaring is not reversible is precisely because you cannot invert to get a unique answer, but instead have two answers.
nazgjunk said:I can indeed come up with x=-1 and y=1, which proves you are right on this one. But to my relatively low-educated head it feels logical though, that if x^2=y^2 then x=y.
This is getting me even more depressed...
matt grime said:It depends upon what you're claiming.
for instance the proposition, for x and y in R
x=y implies x^2=y^2
is true.
It is not a reversible algebraic manipulation.
matt grime said:So despite the fact you can prove it is false you think it ought to be true? Then that is psychological issue not a mathematical one: in face of evidence to the contrary you wish to believe something is true.
dimachka said:ahh, i see what you are saying, so not necessarily reversible, just only allowed to broaden scope, rather than narrow your scope. I can't exactly see how to make a more concrete explanation of this.
nazgjunk said:No, by god. Why did I ever think I was too stubborn? You are far worse. I said it "felt" right, which doesn't mean I believe it. In Dutch class, I feel that it should be answer A, but with some reason I have to admit it is B. OK, this is a crappy example, but I hope you get the point.
It is important to consider the necessary conditions when applying the exponent rule because without them, the calculation may result in an incorrect answer. The necessary conditions provide guidelines for when the exponent rule can be applied, ensuring that the result is accurate.
The necessary conditions for applying the exponent rule are that the base must be the same, the exponents must be added or subtracted, and the base cannot be negative if the exponent is a fraction. All of these conditions must be met in order for the exponent rule to be applied correctly.
If the necessary conditions are not met when applying the exponent rule, the result will be incorrect. This is because the exponent rule requires specific conditions to be met in order to be applied correctly. If these conditions are not met, the calculation may result in a different answer than intended.
No, the necessary conditions cannot be ignored when applying the exponent rule. These conditions are crucial in determining when the exponent rule can be applied and ensuring the accuracy of the calculation. Ignoring the necessary conditions may result in an incorrect answer.
Yes, there are some exceptions to the necessary conditions for applying the exponent rule. For example, the rule can still be applied if the bases are different but can be factored into the same base. However, it is important to note that these exceptions still follow the general guidelines and should be used with caution to ensure accuracy.