Excel Busn Math 59: Annuities Math & Excel

I have created a graphed curve in excel based on data I have entered. I now want to take the formula for the graph, and use it as an excel computation where I can plug in X and get Y, or plug in Y to get X. However, when i try to enter in variations of these equations, I end up with just the wrong answers (based on the data that went into the graph to begin with.

The formulas excel gives me are these:

y = -1.1288x 3 + 23.209x 2 - 166.76x + 430.07 (preferred), or alternately


y = 579.38e -0.574x


So how can I enter this formula so that I can have it pull x from a cell and spit out the answer for y (and the reverse)?

I want to create a function which defines a pulse wave that rises from
0 to 1, stays at one for a bit, lowers to 0, and stays at zero for a
bit.

/ if (t mod 1) <0.25, V(t) = 4* (t mod 1)
| if 0.5 >= (t mod 1) > 0.25, V(t) = 1
V(t) = |
| if 0.75> =(t mod 1) > 0.5, V(t) = 1-4* (0.75-(t mod 1))
\ if 1 > (t mod 1) > 0.75, V(t) = 0

For this pulse wave there are straight rises, falls and flat bottoms
and tops, which I need (and which is why a sine wave can't be used). If
you're still with me, thanks.

I can either put this all into a long excel equation for each cell that
I want this in (there will be about 4 'if' statements and 6 'mod'
statements) or create a UDF, where the t mod 1 only has to be
calculated once.

Any idea out there how much faster/ slower as UDF really is in a case
like this? Also, can you think of an easier way to create this pulse
wave?

As a side note, the t in my program has some ROW() and COLUMN()
dependence, and there will be 200+ cells filled with this equation
(thus, I can't just compute it once and copy the values to each cell).
Caculation speed is important because each cell is being calculated as
the time, t, is advanced by a timer.

Thanks in advance to anyone who takes a stab at this.

-Abe

I need a formula that does this. I have a base number of 300 seconds and want to add 30 seconds to it for every number over 1 so the output would be like this
input 0 and get 0 out
input 1 and get 300 out
input 2 and get 330 out
input 3 and get 360 out
input 4 and get 390 out
and so on. I can't for the life of me get the math down. Can someone please help.

Hi team,

I have the below table and want to produce a figure that will show a rolling
target.
ie: the target for 12 months is 13... for one month someone gets a score of
11. what will be the target score next month to bring them back on target to
end up with 13?

Date TRUE CALLS score to get avg of 13
20/1/2006 11.91
3/2/2006 11.23
17/2/2006 11.33
3/3/2006 11.35
17/3/2006 11.41
31/3/2006 11.60
14/4/2006 11.91
28/4/2006 11.78
12/5/2006 11.68
26/5/2006 11.55
9/6/2006 11.57
23/6/2006 11.58
7/7/2006 11.55
21/7/2006
4/8/2006
18/8/2006
1/9/2006
15/9/2006
29/9/2006
13/10/2006
27/10/2006
10/11/2006
24/11/2006

Your help is much aprieciated

Here's the newest brain teaser:

I would like to be able to obtain round integers only from one number.

For instance, I want to be able to obtain the number
1,2,3,4,5,6,7,8,9,10 from the base number of 10.25

Sound like fun?

My only attempt thus far as I start this challenge is this:

=ROUND(A1*(((9/10)/10)*A1),0)

.... where A1 = 10.25 This will work out to 9 like I am attempting to
do, but has issues in that if the number (10.25) increases beyond 10.27
it rounds itself to 10, and beyond 10.5 it rounds to 10.5. Its a
problem with the 9/10's in there.

Consider this a puzzle and not so much an excel formula, though
knowledge in both is required... Im back to it....

Well it don't do math all too good...
The trouble is because of this I get division by zero, which isn't really there.
At some point the value gets divided by itself, but the result is still busted!
And so are any subsequent results dependent on it!
So I was wondering - why does excel insist on using a value does has absolutely no impact in the long run.

...yet another stupid flaw in the system.

I am new to Excel ,I am try to better my self.I would like to get a job as a mailclerk/data . I find excel to be easy in some parts & hard in others ""Math formulas,HARD""". I was never good at math so I am worry this will hurt me??

Hi, 1st time on this forum in desperation for help.

I have a spreadsheet which does a number of very simple calculations, but for a particular set of numbers, seems to lose the plot. I have a simplification of the problem here if you could look at it.

In A1 place number 7.02
In B1 place number 7.07
In C!, calculate the difference between A1 & B1 ( =A1-B1)
In D1, place number 0.05 ( this will be a limit that C1 becomes reportable)
In E1, do calculation. =IF(ABS(C1)>D1," out of calibration","")

My problem is that the calculation works for all values placed into A1 & B1 except for the above example. In the example shown, calculation in C1 = D1, but fails. For any other values of A1 & B1 which result in C1=D1, calculation works.
Am I going mad?
Thanks.....Peter

Hello All,

I've search everywhere wondering of my example is even possible. In general, I'm assiting a friend's 8 year old daughter to study math. In school, paper wise they would receive something as follows: (WITHOUT the ANSWER 152). This is ony 1 example, there may or not be carry over number in 2 digit addition questions.

96
+56
152

What I would like to produce is the following:

1 1
9 6
+ 5 6
1 5 2

In cell reference above:
A3 +
B1 1
B4 1
C1 1
C2 9
C3 5
C4 5
D2 6
D3 6
D4 2

B1 & C1 are carry over numbers. generated by a formula, this is only one example. Addition could be of many different sequesnces of numbers.

Two things Im looking for, one the 1st number is entered, the carry over number appears above the question, likewise for the remaining columns to the left,

C2 & D2 are the first set of addition
C3& D3 are the second set of numbers to be addded to the first set.
B4, C4 & D4 are the answers the child would answer. The compliction of this is that the child just as with paper and pen would answer right to left

D2 + D3 would equal 12, the child would enter the last number 2, which leaves a remainder of 1 to carry which would appear in C1.

If the answer was not 12, then message X in all occurances of carry over.

C2 + C3 would equal 15, the child would enter the last number 5, which leaves a remainder of 1 to carry which would appear in B1. Giving the child the opprotunity to add C2 + C3 + the carry over C1 (obviously the formula I'm stuck on)

If the answer was not C2, then message X in all occurances of carry over.

Finally, the child would add up B1 which was the carry over from column C, leaving the answer of 152

I'm not sure if this can even be done, never mind devising a formula to create such a spreadsheet.

Thanks in advanced,
adulted (Paul)

i have a sheet set up to give me certain formulas for our payroll tax. for instance,
these are the numbers that show in the columns, they seem to rounded up on their own when needed, which is what i want.

column c = gross = 270.00
column d = Fed 15% = 40.50
column e = SS 6.2% = 16.74
column f = mc 1.45% = 3.92
column g = State 6% = 16.20
column i = Net = 192.65

the problem is this: i have a "Totals" column so that I know how much to send to the IRS each month. It does not add the rounded up figures "shown" but adds the un-rounded figures some how. the problem is that over time these figures are coming up wrong.

for instance, the mc 1.45% column shown above is actually 3.915. after several of these columns, my figures are wrong. take a look.

Date: gross: mc 1.45% shown in cell mc 1.45% actual

3.1.07 1000.00 14.50 14.50
3.5.07 270.00 3.92 3.915
3.12.07 100.00 1.45 1.45
3.19.07 50.00 .73 .725
3.26.07 50.00 .73 .725

totals 21.32 21.315

it gets worse... if you add all of the "shown" mc column, it is actually 21.33

here is the formula i am using for the "Total MC 1.45%" cell =SUM(F3:F60) now i have another problem, i am suppose to match the s.s. tax and the medicare, so i have another cell that is suppose to simply multiply the "Total MC 1.45%" cell by 2. here is the formula i use for that cell. =K10*2 it says that 21.32 x 2 = 42.63 this is how i discovered this mess in the first place.

i hope this is understandable, as i know it's a bit hard to explain without seeing it. any help would be really great, as this is my first month to begin doing this and i need to get this thing right.

thanks in advance.