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Definite Integral and Rectangle Approximations: Geometric Construction and Numer

Definite Integral and Rectangle Approximations: Geometric Construction and Numer
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2018-08-31 07:08
CalculusIntegralGeometric ConstructionSlider Animation
This example demonstrates how to compute definite integrals using geometric constructions and numerical approximation methods. Key mathematical concepts include definite integrals, rectangle approximations (left endpoint, right endpoint, midpoint), trapezoidal approximations, and function graphing. Construction involves GeoGebra commands such as Textfield, Sequence, Translate, LeftSum, Sum, Intersect, Polygon, Integral to build function images, input parameters, calculate approximations, and draw graphs. Suitable for high school students or college freshmen learning calculus fundamentals and geometric construction techniques.

GeoGebra Commands & Parameters

  1. Textfield(f) → InputBox1
  2. Textfield(a) → InputBox2
  3. Textfield(b) → InputBox3
  4. Sequence((a + (i * deltax), 0), i, 1, n, 1) → rightx
  5. Sequence((a + (i * deltax), f(a + (i * deltax))), i, 1, n, 1) → fofrightx
  6. Sequence((a + (i * deltax), 0), i, 0, n - 1, 1) → leftx
  7. Sequence(Midpoint[Element[leftx, i], Element[rightx, i]], i, 1, n, 1) → midpoints
  8. Sequence((a + (i * deltax), f(a + (i * deltax))), i, 1, n, 1) → list1
  9. Translate(list1, (deltax, 0)) → list1'
  10. LeftSum(f, a, b, n) → l
  11. Sequence(x = x(Element[midpoints, i]), i, 1, n, 1) → list2
  12. Sequence(Intersect[f, Element[list2, i], (1.75, 5.909542504884438)], i, 1, n, 1) → list3
  13. Translate(list3, (deltax / 2, 0)) → midpointtopright
  14. Translate(list3, (((-deltax)) / 2, 0)) → midpointtopleft
  15. Translate(midpoints, (deltax / 2, 0)) → midpoints'
  16. Translate(midpoints, (((-deltax)) / 2, 0)) → midpoints'_1
  17. Sequence(Polygon[Element[midpoints'_1, i], Element[midpoints', i], Element[midpointtopright, i], Element[midpointtopleft, i]], i, 1, n, 1) → list4
  18. Sum(list4) → h
  19. Translate(list1, ((-deltax), 0)) → list1'_1
  20. Translate(rightx, ((-deltax), 0)) → rightx'
  21. Sequence(Polygon[Element[rightx, i], Element[list1, i], Element[list1'_1, i], Element[rightx', i]], i, 1, n, 1) → rightrectanglesum
  22. Sum(rightrectanglesum) → j
  23. Intersect(k, p) → F
  24. Intersect(m, k) → G
  25. Polygon(D, E, G, F) → poly1, d_1, e, g_1, f_1
  26. Intersect(m, q) → H
  27. Intersect(p, q) → I
  28. Polygon(D, E, H, I) → poly2, d_2, e_1, h_1, i_1
  29. Intersect(p, r) → J
  30. Intersect(r, m) → K
  31. Polygon(D, E, K, J) → poly3, d_3, e_2, k_1, j_1
  32. Integral(f, a, b) → s
  33. Sequence(Polygon[(a + (i * deltax), 0), (a + ((i + 1) * deltax), 0), (a + ((i + 1) * deltax), f(a + ((i + 1) * deltax))), (a + (i * deltax), f(a + (i * deltax)))], i, 0, n - 1, 1) → list5
  34. Sum(list5) → u