Discussion about math, puzzles, games and fun. Useful symbols: ÷ × ½ √ ∞ ≠ ≤ ≥ ≈ ⇒ ± ∈ Δ θ ∴ ∑ ∫ π -¹ ² ³ °

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I think I'll stick with the name for now, and change it when/if the videos gain some popularity. Understandably, they aren't getting many views right now, since it's the holidays. Thanks for the feedback so far!

Might shift the focus to GCSE/A-level stuff just before the next summer rolls around -- maths videos are always popular around that time.

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What holidays?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.'

'God exists because Mathematics is consistent, and the devil exists because we cannot prove it'

I'm not crazy, my mother had me tested.

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People typically search for maths help videos during other times of the year. For instance: arguably the most popular maths videos are those that may help people with exams, and predictably there is a large peak during the summer exam season. However, most people in the UK and US are not at university or school at the moment, and are unlikely to be looking for maths videos when the year has not yet started (or has just begun).

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Posted two new videos:

**The Argand Diagram** - Introducing the Argand diagram, with some examples of plotting points on it.

**Calculating Powers of i** - We use the fact that i^2 = -1 to calculate any integer power of i.

*Last edited by zetafunc (2015-10-01 00:56:47)*

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Uploaded two more videos.

**Calculating Partial Derivatives** - An introduction to calculating partial derivatives of simple functions.

**Introduction to Summation Notation** - How to interpret summation (sigma) notation, with some basic examples.

*Last edited by zetafunc (2015-10-01 00:49:13)*

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 4,758

Hi zetafunc;

I get a 404 NOT FOUND error when I click on the links to your last two videos, and have noticed that the domain names are missing from the addresses.

I've inserted them into the below versions, which work:

**Calculating Partial Derivatives** - An introduction to calculating partial derivatives of simple functions.

**Introduction to Summation Notation** - How to interpret summation (sigma) notation, with some basic examples.

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

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Hi phrontister, thanks for bringing that to my attention and reposting the links.

I'm not sure why, but previously it seems I was unable to post the domain name in the URL. There's some kind of censor which was removing it entirely, which didn't show up in the post preview. It seems like all the links in the OP have been affected...

*Last edited by zetafunc (2015-10-01 00:49:54)*

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Uploaded two more videos today, on integration by parts.

**Integration by Parts: Basic Examples** - An introduction to integration by parts, demonstrating how to integrate two simple examples -- namely, xsin(x), and xe^(2x).

**Integrating log(x)** - How to find the integral of log(x), using the technique of integration by parts.

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After almost 3 months, here's a new video where we discuss how to find the logarithm of a complex number.

**Logarithm of a Complex Number** - We define the principal logarithm and use it to calculate some logs of complex numbers.

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

Nice vid!

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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After a long hiatus, and following popular demand, here's another contour integration video, where we compute a contour integral using Cauchy's integral formula.

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

I watched the video, helped alot. Thanks for doing it.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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Here's another contour integration video where we integrate a function involving log(x), using an indented semi-circular contour, by defining a non-principal branch of the complex logarithm. It is also a solution video to problem #2 in my Complex Analysis problems thread.

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

Thanks for the vid. I downloaded it for my notes.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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You're welcome -- glad you found it useful.

Here's Contour Integration #7, where I show that by choosing a sector contour instead of a semi-circle.Offline

**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Watched the video, pretty darn good.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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Thanks. I have about 2-3 more videos planned, using the keyhole contour and a vertical semi-circle (i.e. the diameter of the semi-circle is a vertical line). The last one should be pretty cool, because we will use the technique of contour integration to show that a sum can be written like this:

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

That would be interesting.

What do you use to make your vids?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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To write, I use a Ugee graphics tablet from Amazon -- it was the cheapest tablet I could find that the reviews described as good. It's generally easy to use, but sometimes the pen doesn't make contact with the tablet properly so the stuff I write can end up being "skippy" (I think you might have seen a bit of that in the last video, where I had to go over some letters again).

The drawing is done in MS Paint, and I record using HyperCam, a free screen capturing software.

To record, I use a cheap microphone that sits on my desk, and I usually wear headphones so I can hear what the sound quality is like throughout the recording.

*Last edited by zetafunc (2016-08-09 05:35:52)*

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

What is the size of that tablet screen?

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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It is 10 x 6 inches. Here is where I bought it from: https://www.amazon.co.uk/gp/product/B00 … UTF8&psc=1

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**bobbym****bumpkin**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 109,606

Hi;

Okay thanks. I remember looking at them a few years back over at a store called Best Buys which is the major electronic outlet here. The price was higher and the screen smaller.

**In mathematics, you don't understand things. You just get used to them.****If it ain't broke, fix it until it is.**** Always satisfy the Prime Directive of getting the right answer above all else.**

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