How to get Excel to automatically select cells based upon changing parameters ?

Hi

I have a dilemma and I was wondering if there was any way around it.

Basically, I have two columns which show solutions to quadratic and linear equations (roots). The point at which the value in the first column is greater than the second column and also the row before that (i.e. when the first column value is just less than the second column value), is what I am interested in, I then perform linear interpolation between those two values and hence go on to find a speed.

For example:

1, 3, 6
2, 4, 6
5, 4, 5
6, 5, 4
7, 6, 3

My query is, because I have to do iteration to the initial parameters, the values are always changing in those columns, I need excel to automatically select the two values I am intearested in and calculate the speed, rather than me having to look manually in the long list for the turning point and plugging them in to the interpolation equation etc.

Much appreciated

Thanks

Usman

Thanks for the reply.

I have attached the excel sheet.

Column W and X are the 2 columns I want to compare and find the turning point. Those two rows with their corresponding K values(column U) are interpolated which I manually copy to AD - AG, and then on the left hand side, the calculation takes place with the final speed in AB21.

I would like to eliminate the fact I need to manually look up which values are the turning point and eliminate copying and pasting it manually every time I change in parameters highlighted in yellow.

Aeroelasticity.xlsx