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"Interpolation"
Dear all friend, how to interpolation as equation in highlight?
my row of ( fi,Nc ,Nq,Naq ) start from 0 to 50 or more than.
Please help explain us. thank you all in advance.

Dear all friend, how to interpolation as equation in highlight?
my row of ( fi,Nc ,Nq,Naq ) start from 0 to 50 or more than.
Please help explain us. thank you all in advance.

Please attach your worksheet. It's very hard to debug a picture.
What is the error message regarding fi?
There should be no problem for your vectors fi and Nc being large, as shown here:

Success!
Luc
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