Hi,
Weekly additions (Here, x stands for (1+G/100); e.g., 1.01 if G is 1%)
Week 1 I
Week 2 I*x
Week 3 I*x^2.
.
Week n I*x^(n-1)
So cumulative totals each week (this is what you want) will be:
Week 1 I
Week 2 I + I*x)) = I*(1+x)
Week 3 I + I*x + I*x^2 = I*(1+x+^2)
.
.
Week n I*(1+x+x^2+............+ x^(n-1)
This is a gemometric series and the sum is given by the following formula, Sum = I*(x^n - 1)/(x-1).
Remember that x = 1+G/100; so the sum is,
= I*((1+G/100)^n - 1)/(1+G/100-1)
= 100*I/G*((1+G/100)^n- 1)
Note that 'n' in this formula is the week number.
So, as in your example, if I=1,000,000, G= 1%, and W=6 =100*1000,000*(1.01^6-1)
=6152015
Regards,
B. R. Ramachandran
"Maria Garcao" wrote:
Thanks! This seems to do exactly what I want. It's going to take me the rest of the weekend to break it down to understand exactly how it works, but
at least I'll have something to work with once I get back in the office on Monday.
"B. R.Ramachandran" <BRRamac...@discussions.microsoft.com> wrote in
message news:56189461-3D5A-46DD...@microsoft.com...
Hi,
The formula is, 100*I/G*((1+G/100)^W-1), where I is the starting number, Gcontain
is growth in percentage, W is the number of weeks. So when A1 and B1
the starting number and number of weeks respectively, and the weeklygrowth
is 1%,
=100*A1/1*((1.01)^B1-1)
If you want you can place the growth percent in another cell (say C1,format
the cell as a number and not percent) and the formula will be
=100*A1/C1*((1+C1/100)^B1-1)
Note that you might want to round off the result to the nearest integeras,
=INT(100*A1/C1*((1+C1/100)^B1-1)).
Regards,
B. R. Ramachandran
Remember the result
f A1 and B1 contain the starting numberand the number of weeksrespectively,
and if the growth is 1%,
"Maria Garcao" wrote:
The range of values are not in the worksheet itself. Let me give more details on what I want to do.
storedMy problem: I'm trying to calculate the number of rows that will be
thatin a data warehouse fact table over a period of time. My assumption is
butI will be starting with "X" number of rows that will be stored the first
week, and that every week we will be adding another bunch of "X" rows,
"X" will be growing by approximately 1% every week.
manyFor example, lets say "X" is 1,000,000 rows and I want to calculate how
rows will be stored over 6 weeks.
Week 1: 1,000,000
Week 2: 1,010,000
Week 3: 1,020,100
Week 4: 1,030,301
Week 5: 1,040,604
Week 6: 1,051,010
So my sum after 6 weeks would be: 6,152,015
I have two numbers stored in two cells of the worksheet:
Cell A1 = X = "starting" number of rows
Cell A2 = Y = number of weeks to calculate for
where nSo the formula that I want to sum is "=INT(A1*(POWER, 1.01, n-1))",
ranges from 1 to A2.
becauseI don't want populate "n" number of cells and then just sum them up
effects"n" can get quite large, and I want to quickly be able to model the
of changing the value of "n" for different fact tables.
Hopeully this sheds more light on exactly what I'm trying to do.
"B. R.Ramachandran" <BRRamac...@discussions.microsoft.com> wrote in message news:576916F2-4871-4844...@microsoft.com...
Hi,
SigmaIf the range of values are say in A1:An, and you want to calculate
calculatef(Ai) for i = 1 to n where 'f' is a function (without having to
canthe
individual values of f(A1), f(A2)....f(An) and summing them up), you
use
an array formula as follows:.
In a destination cell enter the formula s
=SUM(f(A1:An)) and press CTRL-SHIFT-ENTER.
+ 4For example, if you want to calculate the sum of 2*ln(Ai) + 3*sqrt(Ai)
CTRL-SHIFT-ENTER.forthe contents of cells A1....A10, the formula will be =SUM(2*ln(A1:A10) + 3*SQRT(A1:A10) + 4) confirmed with
Regards,
B. R. Ramachandran
"Maria Garcao" wrote:
likevaluesDoes Excel have a "sigma" function . . . i.e. I want to sum all the
of a formula over a range of values (z = 1 to n). Ideally, I would
ofto
do this within a single function, rather than externalize the range
values in the spreadsheet and then sum those values.
Any help or suggestions would be appreciated.
Hi,
Weekly additions (Here, x stands for (1+G/100); e.g., 1.01 if G is 1%)
Week 1 I
Week 2 I*x
Week 3 I*x^2.
.
Week n I*x^(n-1)
So cumulative totals each week (this is what you want) will be:
Week 1 I
Week 2 I + I*x)) = I*(1+x)
Week 3 I + I*x + I*x^2 = I*(1+x+^2)
.
.
Week n I*(1+x+x^2+............+ x^(n-1)
This is a gemometric series and the sum is given by the following formula, Sum = I*(x^n - 1)/(x-1).
Remember that x = 1+G/100; so the sum is,
= I*((1+G/100)^n - 1)/(1+G/100-1)
= 100*I/G*((1+G/100)^n- 1)
Note that 'n' in this formula is the week number.
So, as in your example, if I=1,000,000, G= 1%, and W=6 =100*1000,000*(1.01^6-1)
=6152015
Regards,
B. R. Ramachandran
"Maria Garcao" wrote:
Thanks! This seems to do exactly what I want. It's going to take me the rest of the weekend to break it down to understand exactly how it works, but
at least I'll have something to work with once I get back in the office on Monday.
"B. R.Ramachandran" <BRRamac...@discussions.microsoft.com> wrote in
message news:56189461-3D5A-46DD...@microsoft.com...
Hi,
The formula is, 100*I/G*((1+G/100)^W-1), where I is the starting number, Gcontain
is growth in percentage, W is the number of weeks. So when A1 and B1
the starting number and number of weeks respectively, and the weeklygrowth
is 1%,
=100*A1/1*((1.01)^B1-1)
If you want you can place the growth percent in another cell (say C1,format
the cell as a number and not percent) and the formula will be
=100*A1/C1*((1+C1/100)^B1-1)
Note that you might want to round off the result to the nearest integeras,
=INT(100*A1/C1*((1+C1/100)^B1-1)).
Regards,
B. R. Ramachandran
Remember the result
f A1 and B1 contain the starting numberand the number of weeksrespectively,
and if the growth is 1%,
"Maria Garcao" wrote:
The range of values are not in the worksheet itself. Let me give more details on what I want to do.
storedMy problem: I'm trying to calculate the number of rows that will be
thatin a data warehouse fact table over a period of time. My assumption is
butI will be starting with "X" number of rows that will be stored the first
week, and that every week we will be adding another bunch of "X" rows,
"X" will be growing by approximately 1% every week.
manyFor example, lets say "X" is 1,000,000 rows and I want to calculate how
rows will be stored over 6 weeks.
Week 1: 1,000,000
Week 2: 1,010,000
Week 3: 1,020,100
Week 4: 1,030,301
Week 5: 1,040,604
Week 6: 1,051,010
So my sum after 6 weeks would be: 6,152,015
I have two numbers stored in two cells of the worksheet:
Cell A1 = X = "starting" number of rows
Cell A2 = Y = number of weeks to calculate for
where nSo the formula that I want to sum is "=INT(A1*(POWER, 1.01, n-1))",
ranges from 1 to A2.
becauseI don't want populate "n" number of cells and then just sum them up
effects"n" can get quite large, and I want to quickly be able to model the
of changing the value of "n" for different fact tables.
Hopeully this sheds more light on exactly what I'm trying to do.
"B. R.Ramachandran" <BRRamac...@discussions.microsoft.com> wrote in message news:576916F2-4871-4844...@microsoft.com...
Hi,
SigmaIf the range of values are say in A1:An, and you want to calculate
calculatef(Ai) for i = 1 to n where 'f' is a function (without having to
canthe
individual values of f(A1), f(A2)....f(An) and summing them up), you
use
an array formula as follows:.
In a destination cell enter the formula s
=SUM(f(A1:An)) and press CTRL-SHIFT-ENTER.
+ 4For example, if you want to calculate the sum of 2*ln(Ai) + 3*sqrt(Ai)
CTRL-SHIFT-ENTER.forthe contents of cells A1....A10, the formula will be =SUM(2*ln(A1:A10) + 3*SQRT(A1:A10) + 4) confirmed with
Regards,
B. R. Ramachandran
"Maria Garcao" wrote:
likevaluesDoes Excel have a "sigma" function . . . i.e. I want to sum all the
of a formula over a range of values (z = 1 to n). Ideally, I would
ofto
do this within a single function, rather than externalize the range
values in the spreadsheet and then sum those values.
Any help or suggestions would be appreciated.
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