Hello,

I am trying to create a summation equation from this algebra equation, would it be possible?

x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x

If so can anyone help me?

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- Dec 14th 2011, 07:23 AMsilver163Create sum expression from algebraic expression
Hello,

I am trying to create a summation equation from this algebra equation, would it be possible?

x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x

If so can anyone help me? - Dec 14th 2011, 07:52 AMemakarovre: Create sum expression from algebraic expression
Strictly speaking, this is not an equation because it lacks the = sign. It's an expression. If by "summation equation" you mean an expression that uses the symbol, then

If you want to simplify that expression, then you can use the formula for the sum of an arithmetic progression:

- Dec 14th 2011, 08:03 AMsilver163re: Create sum expression from algebraic expression
Thank you for the response, I understand that in order to create the equation that symbol is needed but my question is would it be possible to convert the equation I posted into that summation? if so how?

basically it works by set periods for example if the period is set to 3 then the equation would be: x+2x+3x and if the period is set to 4 then the equation would be x+2x+3x+4x - Dec 14th 2011, 08:07 AMemakarovre: Create sum expression from algebraic expression

Edit: If this is not what you want, please explain what you mean by "that summation." - Dec 14th 2011, 08:34 AMsilver163re: Create sum expression from algebraic expression
Hello,

Yes I needed a formula and that one is good. I guess I was thinking that the formula could have been written using the summation symbol? - Dec 14th 2011, 08:40 AMemakarovre: Create sum expression from algebraic expression
The formula with the summation symbol is given in post #2 (you can replace 11 with and add ... in the left-hand side).

- Dec 14th 2011, 04:53 PMsilver163re: Create sum expression from algebraic expression
I haven't dealt with calculus in a while, thank you very much.

- Jan 13th 2012, 01:27 PMsilver163Re: Create sum expression from algebraic expression
Hello,

I wanted to ask if I got these written correctly:

900: 1x+2x+3x+4x+5x+6x+6x+6x+6x+6x+6x+6x

500: 1x+2x+3x+4x+5x+6x+7x+8x+8x+8x+8x+8x

100: 1x+2x+3x+4x+5x+6x+7x+8x+9x+10x+11x+12x

For these would the equation be correct written:

900: S (upper: 5 lower: 1) ix + S (upper:6 lower: 1) 6x where x = 10000

500: S (upper: 5 lower: 7) ix + S (upper:5 lower: 1) 6x where x = 10000

500: S (upper: 12 lower: 1) ix where x = 10000 - Jan 13th 2012, 02:28 PMemakarovRe: Create sum expression from algebraic expression
I don't see the relationship between 900, 500, 100 and the expressions after the colon.

In this forum, you can write [tex]\sum_{i=1}^{12} ix[/tex] to get .

Below (capital Greek sigma) we typically write , not just 1, but above we write just 12 (for example). The notation means the sum where ranges from 1 to 12.

Quote:

500: S (upper: 12 lower: 1) ix where x = 10000

Quote:

500: S (upper: 5 lower: 7) ix + S (upper:5 lower: 1) 6x where x = 10000

- Jan 13th 2012, 07:29 PMsilver163Re: Create sum expression from algebraic expression
The 500, 900 is labeling. but are the calculations correct?

- Jan 14th 2012, 04:46 AMemakarovRe: Create sum expression from algebraic expression
No.

In the explicit sum, 6x occurs 7 times, but in the sigma-expression, it is used only 6 times.

It is not clear what 6x is doing in the sigma-expression and why you have , where the upper limit is less than the lower one. - Jan 14th 2012, 09:41 AMsilver163Re: Create sum expression from algebraic expression
so would it be correct:

? - Jan 14th 2012, 09:48 AMemakarovRe: Create sum expression from algebraic expression
This is not an equation (it does not have an = sign), so I can't say if it's true or false.

- Jan 14th 2012, 12:15 PMsilver163Re: Create sum expression from algebraic expression
ok is this statement true?

+ = 680000 - Jan 14th 2012, 12:30 PMemakarovRe: Create sum expression from algebraic expression
. However, in post #8 the expression labeled 500 has = , which is indeed 680000 for x = 10000.