## UnkleRhaukus Group Title $\infty\times0=$ one year ago one year ago

1. Fox375 Group Title

0!!!!

2. UnkleRhaukus Group Title

@lgbasallote

0

4. satellite73 Group Title

definitely $$\pi$$

5. Fox375 Group Title

@satellite73 IKR

6. UnkleRhaukus Group Title

7. satellite73 Group Title

oh wait, i am wrong it is $$e^2$$ sorry

8. lgbasallote Group Title

you can rewrite $\infty \times 0$ as $\infty \times \frac 1\infty$ right? then it becomes l'hospital...

9. lgbasallote Group Title

assuming of course these are functions...

10. UnkleRhaukus Group Title

there is another way

11. lgbasallote Group Title

really? hmm

12. lgbasallote Group Title

change infinity to 1/0 to make it 0/0?

13. lgbasallote Group Title

either way...it's indeterminate....

14. satellite73 Group Title

if this is a serious question, presumably it is about limits, i.e. if $$\lim_{x\to\infty}f(x)=\infty$$ and $$\lim_{x\to \infty}g(x)=0$$ then what is $\lim_{x\to \infty}f(x)g(x)$ the answer is it could be anything, it depends on $$f$$ and $$g$$ the form is not determined

15. CliffSedge Group Title

$\large a \times b = c$ $\large a=\frac{c}{b}$ $\large b=\frac{c}{a}$ Let a = ∞, b=0 $\large ∞=\frac{c}{0}$ $\large 0=\frac{c}{∞}$ But c/0 is undefined and so is c/∞, right? What if c were positive? What if c were negative?

16. satellite73 Group Title

so it could be $$\pi$$ or it could be $$e^2$$ or it could be anything

17. lgbasallote Group Title

an interesting question though is... $\frac 1 \infty = 0$ therefore... $0 \times \infty = 1$ that should be right?

18. lgbasallote Group Title

just expressing how weird math is

19. satellite73 Group Title

not at all

20. satellite73 Group Title

infinity is not a number, and so $$\frac{1}{\infty}$$ is not a number either

21. CliffSedge Group Title

Agree with @satellite73 To say that 1/∞ = 0, you have to take the limit of 1/x as x-->∞ and then 0 × (x is really really big) still equals 0.

22. UnkleRhaukus Group Title

|dw:1349968485543:dw|

23. lgbasallote Group Title

math is still weird....

24. CliffSedge Group Title

(I'm going to have to go get coffee, then come back for this. Unkle is about to get all Twilight Zone on us, I can feel it.)

25. satellite73 Group Title

you are making short cut statements about limits namely if $\lim_{x\to\infty}f(x)=\infty$ then $\lim_{x\to \infty}\frac{1}{f(x)}=0$

26. lgbasallote Group Title

i never really understood the function of limits...

27. lgbasallote Group Title

math is too ambiguous for me

28. satellite73 Group Title

$$\infty$$ is not a number $$\infty\times 0$$ is not a number $\frac{5}{\infty}$ is not a number

29. CliffSedge Group Title

(aside: Anybody hear the full treatment of 'Hilbert's Hotel?')

30. CliffSedge Group Title

Is the slope of the vertical line +∞ or -∞ @UnkleRhaukus ?

31. UnkleRhaukus Group Title

i dont know what 'Hilbert's Hotel?' is

32. CliffSedge Group Title

Check it out some time. David Deutsch gives a good telling of it in his book, 'The Beginning of Infinity.' (Fantastic book on the philosophy of science; I recommend it to everyone.)

33. UnkleRhaukus Group Title

the product of the slopes of perpendicular lines is

34. CliffSedge Group Title

Yes, but what is the slope of the vertical line?

35. UnkleRhaukus Group Title

$\pm\infty$

36. helder_edwin Group Title

this might help

37. JamesWolf Group Title

infinity is stupid. $\infty + 1 = \infty$ $1 = \infty - \infty = 0$

38. UnkleRhaukus Group Title

$\infty\times 0=-1$

39. JamesWolf Group Title

all the even numbers = $\infty$ which is smaller than all the numbers = $\infty$ so $\infty < \infty$

40. CliffSedge Group Title

$\large 2 \times ∞ \times 0 = -2?$

41. CliffSedge Group Title

@JamesWolf there are different cardinalities of infinity. Research "Aleph Numbers" for more info. The infinity of integers is less than the infinity of real numbers, etc.

42. Jemurray3 Group Title

The bastardization of mathematics that has taken place in this thread is like salt rubbed into a fresh wound of my soul. Is there a legitimate question, or are you guys just playing around? :)

43. 03453660 Group Title

this is definitely an undefined case because any number multiplied with zero become zero and any number multiplied with infinity become infinity that's why both of these cases are possible here therefore we cannot consider one these case separately. thus this is an undefined case.

44. CliffSedge Group Title

@Jemurray3 I don't think there's anything serious going on. Unkle came up with a cute link to slopes of parallel lines, but made the error in saying that vertical lines have a slope, m=∞, which, of course, is false.

45. Coolsector Group Title

if the question is something like lim x->inf of 0*x then it is 0 otherwise we should be more specific about the problem i guess