Since the OP is comparing LINEST with the chart trendline, he must have
already plotted the data. On the assumption that he actually looked at
the plot that he produced, I can only assume that he is interested in
the numerics of the fitting process, not the quality (or lack thereof)
of this particular fit.

Jerry

Tushar Mehta wrote:

If you plot the data you will quickly see that the only trend is a flat
horizontal line or, with the application of a fair dose of imagination,
a slight downward sloping trend.