Set up two columns, one containing the x values and the other containing
f(x) values. The x column should be to the left of the f(x) column, but
they do not have to be adjacent.
Select both columns of data and on the menu select Insert|Chart|XY
(Scatter) and select the first example in the second column of "Chart
sub-types" ("Scatter with data points connected by smoothed Lines
without markers.")
Follow the prompts selecting any desired customizations.
Jerry