OK, I think I have a tough one. Probably not for you guys!
Let's say I have the following data set in two rows where the top row are the x's and the second row the y's. Like this:
[TABLE="width: 500"]
<tbody>[TR]
[TD="align: center"]1[/TD]
[TD="align: center"]2[/TD]
[TD="align: center"]3[/TD]
[TD="align: center"]4[/TD]
[TD="align: center"]5[/TD]
[TD="align: center"]6[/TD]
[/TR]
[TR]
[TD="align: center"]1530[/TD]
[TD="align: center"]1418[/TD]
[TD="align: center"]1046[/TD]
[TD="align: center"]1088[/TD]
[TD="align: center"]1137[/TD]
[TD="align: center"]1045[/TD]
[/TR]
</tbody>[/TABLE]
Assume the first cell is A1.
The following formulas will get me the two values I need to calculate an exponential trendline y = c *e ^(b * x)
c=EXP(INDEX(LINEST(LN(A1:F1),A2:F2),1,2))
b=INDEX(LINEST(LN(A1:F1),A2:F2),1)
If I do this in a chart, I will match. In a chart if I remove a value, say the 1046, it will recalculate c and b and display the adjusted trend.
The formula however will give me an error.
Now finally to my question: How can I alter my formulas to recalculate properly if I remove one or more values?
I hope I stated that clearly enough
Thanks.
Let's say I have the following data set in two rows where the top row are the x's and the second row the y's. Like this:
[TABLE="width: 500"]
<tbody>[TR]
[TD="align: center"]1[/TD]
[TD="align: center"]2[/TD]
[TD="align: center"]3[/TD]
[TD="align: center"]4[/TD]
[TD="align: center"]5[/TD]
[TD="align: center"]6[/TD]
[/TR]
[TR]
[TD="align: center"]1530[/TD]
[TD="align: center"]1418[/TD]
[TD="align: center"]1046[/TD]
[TD="align: center"]1088[/TD]
[TD="align: center"]1137[/TD]
[TD="align: center"]1045[/TD]
[/TR]
</tbody>[/TABLE]
Assume the first cell is A1.
The following formulas will get me the two values I need to calculate an exponential trendline y = c *e ^(b * x)
c=EXP(INDEX(LINEST(LN(A1:F1),A2:F2),1,2))
b=INDEX(LINEST(LN(A1:F1),A2:F2),1)
If I do this in a chart, I will match. In a chart if I remove a value, say the 1046, it will recalculate c and b and display the adjusted trend.
The formula however will give me an error.
Now finally to my question: How can I alter my formulas to recalculate properly if I remove one or more values?
I hope I stated that clearly enough

Thanks.