矩形法估算积分

GeoGebra 命令及参数

1. Textfield(f) → inputBox1
2. Point(xAxis) → A
3. Point(xAxis) → B
4. Sequence(x(A) + (i * dx), i, 0, n) → subint
5. Take(subint, 1, n) → left
6. Take(subint, 2, n + 1) → right
7. Sequence(Polygon[(Element[left, i], 0), (Element[right, i], 0), (Element[right, i], Element[rightheights, i]), (Element[left, i], Element[rightheights, i])], i, 1, n) → rightRect
8. Sequence(Polygon[(Element[left, i], 0), (Element[right, i], 0), (Element[right, i], Element[leftheights, i]), (Element[left, i], Element[leftheights, i])], i, 1, n) → leftRect
9. IntegralBetween(((-(x(l) / y(l))) * x) - z(l) / y(l), f, x(B), x(A)) → Area