linest()
3rd order polynomial fitting coefficients, e.g.
y = a0 + a1*x + a2*x^2 + a3*x^3
a0 = INDEX(LINEST(D2:D8,$A$2:$C$8,1,1),1,4)
a1 = INDEX(LINEST(D2:D8,$A$2:$C$8,1,1),1,3)
a2 = INDEX(LINEST(D2:D8,$A$2:$C$8,1,1),1,2)
a3 = INDEX(LINEST(D2:D8,$A$2:$C$8,1,1),1)
Chose a box range on the table
type LINEST(D2:D8,$A$2:$C$8,1,1) in the function input blank bar
Ctrl+Shift+Enter
the output is
a3 a2 a1 a0
se3 se2 se1 se0 (standard error)
...