Basic Summation Questions with two different growth rates

[Farhasnat]

Is there is a easy way to write this formula ? Essentially what i am trying to do is the take the summation of ($D$13*$C13*$C8) and add % growth of (1+C9) AND % growth of (1+C10)

This formula is also calculating incorrectly:

=(($D$13*$C13*$C8)*(1+C9))+(($D$13*$C13*$C8)*(1+C10))

Any help would be highly helpful

[MrShorty]

I see no syntax or similar error, so I am guessing the problem is that you have incorrectly defined the calculation (something outside of Excel).

When I think of applying two "growth rates", my first expectation is a simple product -- y=x*rate1*rate2. Your calculation looks like you are doing something different -- y=x*rate1+x*rate2=x*(rate1+rate2).

Of course, at this point I am just guessing at what you want to do. I think that we need to understand exactly what calculation you want to perform before we can talk about how to program that calculation into the spreadsheet. Help us understand the calculation you want to perform, and we should be able to help program that calculation into the spreadsheet.

[Farhasnat]

Thank you for you reply. Please note the example below:

I have X = 1000
Step 2: Multiply X by 2 other variables = 1000 * 2* 13
Now add % Y to the value of step 2= 2%
And add % Z to the value of step 2 = 1%
The total value is = Step 2 + (1000* Y) + (1000* Z)

I am just wondering if there is simpler way to write this formula.

Thank you again for you help

[MrShorty]

I know algebra is supposed to be inapplicable to real life, but let's start with some algebra:

Writing the expression out in algebraic notation where A=2, B=13, Y=0.02 and Z=0.01 and are all constants. R is for result and X is out input value:

R=X*A*B+X*Y+X*Z
we can factor X out of the right side.
R=X*(A*B+Y+Z).

Is the second version "simpler" than the first one? I don't know; one would probably have to be pretty specific at what it means to be simpler. Which is easier for you to program, debug, and edit into the spreadsheet? I would probably decide based on that criteria.