1. first off you're missing the second argument of SLOPE function
which is "known_x's" i.e. 1!$d$5:$d$45000

2. this array-entered (with CTRL+SHIFT+ENTER instead of simply using
ENTER, if the array-formula is entered correctly you will see it in
curly braces: { before + sign and } in the end) formula gives me a
numeric result:

=SLOPE(IF(ISNUMBER(MATCH(DATE(YEAR('1'!$C$5:$C$12) ,MONTH('1'!$C$5:$C
$12),DAY('1'!$C$5:$C$12)),'2'!A1:A2,0)),'1'!$D$5:$ D$12),'1'!$C$5:$C
$12)

although I'm not sure if this is the desired one

On 29 Kwi, 06:04, beto wrote:
------ *I have 4 columns : <---------

COLUMN A: Dates (ex. 1/15/2009)
COLUMN B: Time *(ex. 1:35:24 AM)
COLUMN C: Dates and Time added and shown in the format ” dd/mm/yyyy hh/mm "
and converted to a number gives: (ex. *40035.01 ) this would be the "X-axis
data"
COLUMN D: *" Y-Axis Data "

----- Excell sheet "1" <------

* * A * * * * * * * * * B * * * * * * * * * C * * * * * * * * D
1/15/2009 * *1:35:24 AM * *40035.01 * * * *1234
1/15/2009 * *2:15:20 AM * *40035.11 * * * *2345
1/15/2009 * *3:24:31 AM * *40035.26 * * * *2456
1/16/2009 * *1:15:20 AM * *40036.01 * * * *3456
1/16/2009 * *7:30:23 AM * *40036.13 * * * *4567
1/17/2009 * *9:24:23 AM * *40037.19 * * * *5678
1/18/2009 * *3:35:23 AM * *40038.25 * * * *6789
1/19/2009 * *3:37:23 AM * *40039.25 * * * *6789

------------ Excel sheet "2" <----------
I want to create an array that automatically takes the values that
correspond from the date 1/16/2009 to 1/18/2009 and give me the slopes from
the values located on "COLUMN D (Y-axis )" and " COLUMN C (X- axis )" from
the desire range of dates.

I Tried the following:

--------- worksheet "2" <-----------
Cell A1: *1/16/2009
Cell A2: *1/18/2009

Using as range A1 to A2 (1/16/2009, 1/17/2009, 1/18/2009)

Cell “B2” :
=Slope(IF(ISNUMBER(MATCH(1!$C$5:$C$45000,2!A1:A2,0 )),1!$d$5:$d$45000))

That function is the one I am trying to use but it doesn't work, maybe the
slope can not be combined with other functions, but to be honest I do not
know how to do it.

Thanks! I hope someone can help..... ????????

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asdf