#### QUESTION

I am trying to graphically represent the error in a Riemann sum. My current code looks like:

```
Show[DiscretePlot[Log[t], {t, 1, 10, 1}, ExtentSize -> Left, PlotMarkers -> "Point"],
Plot[Log[t], {t, 1, 10}]]
```

I would know like to plot JUST the curve-linear triangles above the plot of ln(x) that represents the error in the Riemann Sum.

#### ANSWER

If only visual matters - then use filling to mask everything under the curve:

```
Show[DiscretePlot[Log[t], {t, 1, 10, 1}, ExtentSize -> Left, PlotMarkers -> "Point"],
Plot[Log[t], {t, 1, 10}, Filling -> Bottom, FillingStyle -> White]]
```

You can also get crafty to show with color varying size of error triangles. And also give a vague opaque hint on underlying vertical rectangles - as their discreteness is the reason for error:

```
Show[
DiscretePlot[Log[t], {t, 1, 10, 1}, ExtentSize -> Left,
ExtentMarkers -> {"Filled", "Empty"}, ColorFunction -> "Rainbow",
ExtentElementFunction -> "GlassRectangle"],
Plot[Log[t], {t, 1, 10}, Filling -> Bottom,
FillingStyle -> Directive[White, Opacity[.8]]],
DiscretePlot[Log[t], {t, 1, 10, 1},
PlotStyle -> Directive[Dashed, Thick, Black]] ]
```

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