The main idea is to take your X-points and draw them on the chart. Then interpolate between them using some reasonable interpolation function. You can use linear interpolation, quadric B-splines, etc. Usually, if you have no specific reason to believe that the points are a higher-order function (e.g., N 4 ), you want to stick to a relatively low-level interpolation function.
Once you have done this, you have a (essentially) continuous line on your chart. To get your Y points, you simply select Y points evenly spaced along the X axis.
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