trend excluding errors or ""
 

Hello all,

my real issue is a chart problem.
I have a chart, which runs from the 1st to last day of a month.
For example today is the 21st, so I have data up to the 21st,
except for the Saturdays and Sundays.

What I'd like to have is a trendline, which runs from the 1st
to the 21st, ignoring the Saturdays and Sundays and ending
at the 21st.

My idea is to create a formula to calculate the required trend
and show it as a data series in the chart, but I not able to
work with error values or "" (for Sat & Sun) in the trend formula.

Any suggestion, also other approaches are highly appreciated.

Thanks in advance
Werner