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Z__

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A simple math question.
October 18, 2011, 01:12pm
(465) | (36)
I can't figure out how to word the question broadly on google.

But, say you wanted to multiply a number by two, 90 times.
Instead of doing..

1x2=2
2x2=4
4x2=8

And so on and so forth until you've got 90 products, is there an equation you can type to figure out the end result without doing each problem one by one 90 times?



this fucking music we could send to aliens
to warn? them we dont joke here

ZVLKX

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Civilcocks


Gibble
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A simple math question. October 19, 2011, 07:01am
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I'm pretty sure it's Nx(2^90)
N being the number.

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UnSuspecting_Evil

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A simple math question. October 20, 2011, 06:16pm
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Yes that was my thought exactly ^^


Z__

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A simple math question. October 27, 2011, 12:43pm
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Thanks! Appreciate it!



this fucking music we could send to aliens
to warn? them we dont joke here
nabrendel
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A simple math question. October 27, 2011, 02:47pm
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i just dropped in here but I'm not sure that N(2^90) is going to get you what you want.

Is what you want something like: (N*2) + (N*2) .. 90 times? (which is what a number times two 90 times and then added)

or is it this: (N*2^x) + (N*2^(x+1)) etc. where X runs 1 through 90. (Which is a number times every power of 2, up to 90, and then added together)?

Sorry years of Math just took over :-)


The answer to the most important question in the universe is.... 42

Z__

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A simple math question. October 28, 2011, 12:00am
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Nah no addition required. Like, all that confused me right there.

It makes sense in my head but I can't put it into words. Like, I'm trying to double a number 90 times. The double of 1 is 2, the double of 2 is 4, the double of 4 is 8, the double of 8 is 16, the double of 16 is 32, until I've done that 90 times.

I think the first way did it. I got 10 to the 27th power. But there's no way to verify it without doing it the long way, which I lack the patience for.



this fucking music we could send to aliens
to warn? them we dont joke here
nabrendel
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A simple math question. October 28, 2011, 12:42pm
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Gotcha, see a N^x means more that you're multiplying the number, by itself, x times. Which is not what you're looking for; Unless you're talking about just taking 2, in which case yes 10^27 is correct.

If you want a generic way to do any number I'd suggest opening an Excel sheet and entering this in a cell (=X); where X is the number. Then in the cell below it do (=above cell *2); where you've entered in the location of the number above and then hit enter. Now, just select the second cell and you'll see like an outline and you'd be able to drag it down 90 lines, and at the end you'd find out the answer.


The answer to the most important question in the universe is.... 42

Repentia

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A simple math question. October 28, 2011, 01:07pm
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Which is exactly the same as multiplying it by 2^90

--


Nakago

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Flopsy
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A simple math question. November 07, 2011, 07:31pm
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"If you want a generic way to do any number I'd suggest opening an Excel sheet..."

This is where I started laughing in this thread.


ZVLKX

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Civilcocks


Gibble
Posts: 1969
A simple math question. November 15, 2011, 03:19pm
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die
Alternatively you could come up with a hypothesis that doubling a number X amount of times will result in N(2^X) and test it on a few low values of X (so it's easier to work out than using big numbers).

For example if X=3, then the equation would be Nx(2^3) which simplifies to 8N
Working it out the long way:
N x 2 = 2N
2N x 2 = 4N
4N x 2 = 8N

See that it works and would therefore work for 90 times and voila, you've actually used your brain and know what to do next time you come across a similar problem.


I've probably gone into this more than necessary but Excel spreadsheets die

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Tabneo
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A simple math question. January 30, 2012, 04:19am
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there is a Simple way to come up with the Correct answer to your math problem... First let me point out that you are sitting at a computer, there is No Calculator better then that. Second let me point out, the problem you're looking at is an Exponential Growth problem. so the proper formula is g(x) = 2^x you can find it right here http://www.purplemath.com/modules/expofcns.htm

By the way excel will Chew up most or all of you're system Resources just to give you that answer to 90 when a simple Graphing program, a .bat File or even a program thrown together will give you the same results in much less time (and yes I Wrote a Program in under 2 Mins to get the correct answer)

also you should note that if you are looking at Binary that the most it goes to 2^8 when dealing with computers


Edited by: Tabneo at January 30, 2012, 04:23am


kuntface

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A simple math question. September 21, 2012, 05:21pm
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i do not understand this wow...im not saying im stupid or anything but it just seems complicated


natio2

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A simple math question. September 25, 2012, 07:25am
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Why don't you just use excel and sum the products?...
Plus isnt this just the 90 byte binary number *2?

Just noticed how super old this thread is, sorry about that.

Edited by: natio2 at September 25, 2012, 07:30am


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