# Microsoft Office Application Help - Excel Help forum > Excel General >  >  What does E mean in my equation?

## mcwee72

Guys,

I've worked out a graph and I'm trying to work out the formula, but my equation display a E.

What does the E mean?

y = 1E-06x5 - 0.0002x4 + 0.0161x3 - 0.4893x2 + 7.5295x - 20.87


The above is taken from a graph from the values:

Length	Reading
10	19
15	25
20	27
25	30
30	34
35	37
40	39
45	42
50	43
55	44


Thanks

----------


## DonkeyOte

Scientific Notation

1E-06

0.000001

or

=1*10^-6

(at least that's how I read it...)


Hopefully one of the Math guys can help you get to the bottom of it (properly)

----------


## mcwee72

Thanks

I've tired to work out a different formula... on the excel sheet attached the formula works up to length 15 then onwards goes complete off...??


Any Idea whats going on?

It's doing my head in....

----------


## zbor

You X^4 factor becomes dominant.

If you need this line continue grow lineary then aproximate it with linear function

= 0,6731*D6 + 13,546

----------


## mcwee72

> You X^4 factor becomes dominant.
> 
> If you need this line continue grow lineary then aproximate it with linear function
> 
> = 0,6731*D6 + 13,546



Sorry I don't understand what you mean.

Should I use a linear treadline instead of a polynomial, in which case the polynomial thread line fits best instead of the linear?

Thanks

----------


## zbor

There is no general answer. Everything depends on what you want to achieve...

Look for example this picture:

http://img4.imageshack.us/img4/2236/86011736.jpg

If you wish some precise aproximation in some short interval (in the middle) you should use SIN function (black curve).
But that would give you HUGE mistake as you go further.

If you want some aproximation in the side you should use linear function (red line) wich will give you big mistake in the middle.

If you want to combine both of them you should use some square function (blue line) wich will give you biggest difference in small intervals but better aproximation on whole image.

Now.. If you have more aditional points (green arrow) you can't do that anymore with simple functions now you need to take some polynomial fuction wich will give you best aproximation in this interwal but on further picture... who knows where it going?!

So for best aproximation you should:

a) take as much points as you can
b) keep aproximation in that range... going to far will give you unexpected results
c) you can combine few smaller functions like: if less than for example 10 use linear aproximation (green arrow) else use square aproximation if less than 50 else.. etc...

(smaller function means into smaller intervals)...

maybe shg would give you better explanation and more ideas but you should have more math knowledge at this point (and less excel) so you should take some google searching I guess....

----------


## teylyn

mcwee72, this is very close to a duplicate post. You asked the same question in a follow-up post of another thread. Please don't stir up the same issue in separate threads, when people are already trying to help you there.

For the benefit of the other contributors, here's the link to the other thread: http://www.excelforum.com/excel-work...lculation.html

----------


## Someone on earth

I found out a easier way of explaining, that is (not exactly the easier way, I'm pretty sure we're talking about 2 different things.):

1.11E+09=1,110,000,000

From the example, we can see that 1.11 have something to do with E in the answer. So, my way of explaining is 
1.11E+09=1.11*1,000,000,000=1,110,000,000
E+09 = 1,000,000,000
+09= The number of zeros that need to be added behind the "E", or 1.

So there is no exact explanation for E, but the "E" quotation is actually to the "+09"

So,
1.00E+00=1
2.00E+00=2
1.10E+03=1,100

Or millions and above,

1.00E+09=1,000,000,000
1.11E+12=1,110,000,000,000
2.00E+15=2,000,000,000,000,000
3.00E+18=3,000,000,000,000,000,000
5.55E+21=5,550,000,000,000,000,000,000


And, they only show 2 decimal points RIGHT AFTER the "E", so if your number is like 3.4654541687465468167E+06, it will only show 3.47E+06 because they rounded it up.

I'm not sure if it works for Excel 2010. I'm sure it will work for Excel 2007.

Hope my explaining helped you.  :Smilie:

----------


## zbor

Thx for your comment but there's no point to restore 2 old year post.

Closed

----------

