Tried to form a slope equation for the polynomial trendline type with the date-time type value, but I couldn't be able to form a slope equation. here is the expected output image for reference. I didn't get any solution can you please help me to form a polynomial equation. Also, the R square value for exponential trendline type is different from the excel R square value for date-time type value when proceeding with the steps you gave above. Can you please help me with this issue?
Polynomial slope equation: