Anything Math
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22-02-2017, 06:36 AM (This post was last modified: 22-02-2017 06:40 AM by whateverist.)
RE: Anything Math
Along the lines of Colonel Kernal's opening proofs we could ask for a proof that the product of two odd numbers must itself be odd.

For younger children it is interesting to just ask them to make a convincing argument that this and similar statements are true. The variety of reasoning you can elicit are pretty cool.

For this example one approach would be to work from the realization that even numbers all contain a factor of 2, and, that the product of two numbers results in the conjoining of its factors. For example 12 • 15 = 2•2•3 • 3•5 or 2^2 • 3^2 • 5. Since their product contains at least one factor of 2, it is even. Contrariwise, the product of 15 and 7 contains only odd factors: 3, 5 and 7 and therefore -containing no factor of 2- is not even. In general, the product of any two odd numbers will have to be odd since unless one of the numbers contains a factor of two the product cannot contain a factor of 2 either.

Or one could take an area model approach and work with the definition of odd numbers given by Kernal. So the product of two odd numbers J and K can be thought of as product of two numbers that can be written as 2n+1. So let J = 2j+1 and K = 2k + 1, where j and k are integers. Then their product can be represented as the area of a rectangle with those dimensions:

_____ 2j___+___1

2k___ 2(2jk)___2k
+
1____ 2j_______1

So the product of J and K = 2(2jk) + 2k + 2j + 1 = 2(2jk + k + j) + 1
and since 2jk + k + j is an integer, it follows that twice that integer plus one must be odd.

“Tiger got to hunt, bird got to fly;
Man got to sit and wonder 'why, why, why?'
Tiger got to sleep, bird got to land;
Man got to tell himself he understand.”

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22-02-2017, 07:26 AM
RE: Anything Math
(22-02-2017 12:28 AM)Full Circle Wrote:  How do I calculate the following.


ummmm ... use a tool? 1.728%.

#sigh
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22-02-2017, 11:53 AM
RE: Anything Math



"If we are honest—and scientists have to be—we must admit that religion is a jumble of false assertions, with no basis in reality.
The very idea of God is a product of the human imagination."
- Paul Dirac
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22-02-2017, 12:03 PM
RE: Anything Math
For those that know some elementary programming in any language and want to practice with some awesome math puzzles, try Project Euler.

I have finished through #22. They can be pretty difficult, but they are rewarding as hell.

"Fix reason firmly in her seat, and call to her tribunal every fact, every opinion. Question with boldness even the existence of a God; because, if there be one, he must more approve of the homage of reason, than that of blindfolded fear." ~ Thomas Jefferson
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22-02-2017, 12:52 PM
RE: Anything Math
(22-02-2017 12:03 PM)SteelCurtain Wrote:  For those that know some elementary programming in any language and want to practice with some awesome math puzzles, try Project Euler.

I have finished through #22. They can be pretty difficult, but they are rewarding as hell.

Hey! Welcome!
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22-02-2017, 11:02 PM
RE: Anything Math
(22-02-2017 02:48 AM)Robvalue Wrote:  Is the value of T increasing during the sum, 1, 2, 3... I imagine so? Or is it fixed as being the total number?

And I see the added cash is staggered, so would T be in months giving lots of zero terms...? I've read the article but it doesn't seem to give a lot of detail.

Yes T is increasing daily, the additional sums will be staggered and different each time.
Weeping

“I am quite sure now that often, very often, in matters concerning religion and politics a man’s reasoning powers are not above the monkey’s.”~Mark Twain
“Ocean: A body of water occupying about two-thirds of a world made for man - who has no gills.”~ Ambrose Bierce
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22-02-2017, 11:04 PM
RE: Anything Math
(22-02-2017 07:26 AM)GirlyMan Wrote:  
(22-02-2017 12:28 AM)Full Circle Wrote:  How do I calculate the following.


ummmm ... use a tool? 1.728%.

Have I told you lately that I have a man-crush on you? Heart

“I am quite sure now that often, very often, in matters concerning religion and politics a man’s reasoning powers are not above the monkey’s.”~Mark Twain
“Ocean: A body of water occupying about two-thirds of a world made for man - who has no gills.”~ Ambrose Bierce
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23-02-2017, 10:54 PM
RE: Anything Math
Just watched this video and guess what? Excel 2013 has a built in formula called RRI. Banana_zorro

Begins at 7 min or so




Great video, helped me tremendously!

“I am quite sure now that often, very often, in matters concerning religion and politics a man’s reasoning powers are not above the monkey’s.”~Mark Twain
“Ocean: A body of water occupying about two-thirds of a world made for man - who has no gills.”~ Ambrose Bierce
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24-02-2017, 01:04 AM
RE: Anything Math
How about this for a spooky coincidence?

Just after reading this thread about calculating IRRs, I continued with my bookkeeping studies. One of the next topics I learnt was... calculating IRRs!

The method I need to use approximates the answer by linear interpolation. I'm really motoring again, after a long period of having to stop my studies due to brain fog. I'm nearly ready for my next exam! Then 4 more units to go.

I have a website here which discusses the issues and terminology surrounding religion and atheism. It's hopefully user friendly to all.
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26-02-2017, 01:45 PM
RE: Anything Math
(22-02-2017 12:28 AM)Full Circle Wrote:  The IRR is the interest rate, also called the discount rate, that is required to bring the net present value (NPV) to zero. That is, the interest rate that would result in the present value of the capital investment, or cash outflow, being equal to the value of the total returns over time, or cash inflow.

That's about as clear as a shit sandwich. Jesus. Someone needs to rewrite that.

What do you need to calculate? This IRR thing? The page you linked has instructions for how to get Excel to do it automagically. I vote do that if all you want is the IRR. If you want something in-depth, for what purpose are you calculating it?

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(06-02-2014 03:47 PM)Momsurroundedbyboys Wrote:  And I'm giving myself a conclusion again from all the facepalming.
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