# Is this guy credible?

1. Jan 7, 2012

### tahayassen

Can anyone listen to two or three of his videos and tell me if he made any mistakes in his videos?

Last edited by a moderator: Sep 25, 2014
2. Jan 7, 2012

### morphism

He is being intentionally fast and loose with his math, probably to stir up controversy and gain more views. The fact of the matter is that whenever you deal with infinite sums in such a manner, you must pay attention to issues of "convergence". You simply cannot manipulate divergent (and even some convergent) infinite sums as you would finite sums and expect everything to be fine.

If you tell us what your mathematical background is we might be able to suggest some reading on what's going on.

3. Jan 7, 2012

### tahayassen

I'm taking Grade 12 Advanced Functions. I'm going to start Calculus next semester. We're almost done this semester.

4. Jan 8, 2012

### Jamma

I looked at his videos, and they seem fun and mostly correct (although he skips a lot of details for you to learn all that much).

Note that you shouldn't say that this limit converges to -1. When he says that this sum IS -1, he's just being controversial, but in some sense we can view this sum as being -1

http://en.wikipedia.org/wiki/1_−_2_+_3_−_4_+_·_·_·

I don't know all that much about the uses of this, but apparently there are uses. But just remember, this sum is equal to -1 in only a very abstract way and he should really have said this since the sum doesn't converge.

5. Jan 15, 2012

### Containment

Well there is one that talked about the arrow of time and it gave an idea to ponder so I guess I like them :)

6. Jan 15, 2012

### Dickfore

He is using an analytic continuation of the geometric series:
$$f(z) = \sum_{k = 0}^{\infty}{z^{k}} = \frac{1}{1 - z}, \ \vert z \vert < 1$$
The sum is only convergent within the circle of radius 1 in the complex plane. But, in this region of convergence, it converges towards a simple algebraic function that is defined everywhere, but $z = 1$, which is a simple pole (and it determines the radius of convergence of the series). What he is calculating is basically $f(2) = -1$. The involved procedure is the one used in evaluating the sum of a geometric series.

7. Jan 15, 2012

### tahayassen

Can anyone clearly explain this video?

Last edited by a moderator: Sep 25, 2014
8. Jan 15, 2012

### Jamma

What exactly is confusing about it, it seems pretty well explained already to me.

9. Jan 18, 2012