Non Linear Scatter plot, need to find y value
 

Hi,

There are lots of people asking this question but there is never an answer that works. I have a non linear scatter plot. I want to find some y values for given x values from the plot. A trend line will not work. Ananlysing exisiting data will not work, I want to read from the chart.

I have a little example attached.

I want to use 10 values to plot a curved scatter plot chart, then create a list of y values from given x values to plot another chart, this time a linear chart to see if it close to the curved one..... The second chart will be many x values evenly spaced to try to simulate the original curve using small straight lines.

I think FEvaluate_Bezier is possibly the answer but I am having problems applying it.

Any help would be great, thank you....

Update, solved...

I used the FEvaluate_Bezier solution that Brian created and added some of my ugly VBA to copy the correct formulae and values for the chart.

Now you can state x values for time (ten values) and the plot creates a curve, then the FEvaluate_Bezier reads back values for a regular step interval, then it plots these new values so you can see how straight line and rounding of values effects the simulation.

Non Linear Scatter plot, need to find y value
 

If you are happy with a linear interpolation, then paste
=FORECAST(D2,OFFSET($A$1,MATCH(D2,$A$2:$A$11),1,2, 1),OFFSET($A$1,MATCH(D2,$A$2:$A$11),0,2,1))
into E2 in the
"Mine" sheet and copy down.

It has exactly the same effect as the "Done" sheet.