圆盘法计算旋转体体积
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这个范例演示了如何使用圆盘法计算旋转体的体积。涉及的核心数学概念是定积分和旋转体体积计算。作图要点包括使用Sequence、Rotate、Integral、If、Surface、Polygon、RectangleSum等GeoGebra命令和对象来构建图形和计算体积。适合高中和大学低年级学生学习微积分和立体几何。
GeoGebra 命令及参数
Sequence(Polygon[((k * hx), g(((k + p) * hx))), (((k + 1) * hx), g(((k + p) * hx))), (((k + 1) * hx), f(((k + p) * hx))), ((k * hx), f(((k + p) * hx)))], k, 0, m - 1) → VRectanglesRotate(B, α, a) → B'Integral((((2 * π) * (1 + x)) * (f(x) - g(x))), 0, 9) → VolShellIntegralIntegral((π * ((1 + gI(y))^(2) - (1 + fI(y))^(2))), 0, 3) → VolWasherIntegralSequence(Polygon[(gI(((k + p) * hy)), (k * hy)), (fI(((k + p) * hy)), (k * hy)), (fI(((k + p) * hy)), ((k + 1) * hy)), (gI(((k + p) * hy)), ((k + 1) * hy))], k, 0, m - 1) → HRectanglesRotate(HRectangles, (-α), a) → HRectangles'Rotate(VRectangles, (-α), a) → VRectangles'If(togSurf ≟ 1, "Hide surface", "Show surface") → ShowSurfaceSurface(-1 + ((1 + gI(u)) * cos(β)), u, ((1 + gI(u)) * sin(β)), u, 0, 3, β, 0, (2 * π)) → OuterSurface(-1 + ((1 + fI(u)) * cos(β)), u, ((1 + fI(u)) * sin(β)), u, 0, 3, β, 0, (2 * π)) → InnerIf(togSH ≟ 1, "Use washers", "Use shells") → ShellWasherSurface(-1 + ((1 + u) * cos(β)), f(((m - 1 + p) * hx)), ((1 + u) * sin(β)), u, ((m - 1) * hx), (m * hx), β, 0, α) → ShellsBack1Surface(-1 + ((1 + u) * cos(β)), (g(m - 1 + p) * hx), ((1 + u) * sin(β)), u, ((m - 1) * hx), (m * hx), β, 0, α) → ShellsFront1Surface(-1 + ((1 + ((m - 1) * hx)) * cos(β)), v, ((1 + ((m - 1) * hx)) * sin(β)), v, g(((m - 1 + p) * hx)), f(((m - 1 + p) * hx)), β, 0, α) → ShellsInner1Surface(-1 + ((1 + (m * hx)) * cos(β)), v, ((1 + (m * hx)) * sin(β)), v, g(((m - 1 + p) * hx)), f(((m - 1 + p) * hx)), β, 0, α) → ShellsOuter1Polygon((gI(((m - 1 + p) * hy)), ((m - 1) * hy)), (fI(((m - 1 + p) * hy)), ((m - 1) * hy)), (fI(((m - 1 + p) * hy)), (m * hy)), (gI(((m - 1 + p) * hy)), (m * hy))) → RectWash, b, c, d, ePolygon((((m - 1) * hx), g(((m - 1 + p) * hx))), (((m - 1) * hx), f(((m - 1 + p) * hx))), ((m * hx), f(((m - 1 + p) * hx))), ((m * hx), g(((m - 1 + p) * hx)))) → RectShell, h, i, j, kSurface(-1 + ((1 + fI(((m - 1 + p) * hy))) * cos(β)), v, ((1 + fI(((m - 1 + p) * hy))) * sin(β)), v, ((m - 1) * hy), (m * hy), β, 0, α) → WasherInner1Surface(-1 + ((1 + gI(((m - 1 + p) * hy))) * cos(β)), v, ((1 + gI(((m - 1 + p) * hy))) * sin(β)), v, ((m - 1) * hy), (m * hy), β, 0, α) → WashOuter1Surface(-1 + ((1 + u) * cos(β)), ((m - 1) * hy), ((1 + u) * sin(β)), u, fI(((m - 1 + p) * hy)), gI(((m - 1 + p) * hy)), β, 0, α) → WashFront1Surface(-1 + ((1 + u) * cos(β)), (m * hy), ((1 + u) * sin(β)), u, fI(((m - 1 + p) * hy)), gI(((m - 1 + p) * hy)), β, 0, α) → WashBack1RectangleSum((((2 * π) * (1 + x)) * (sqrt(x) - x / 3)), 0, (m * hx), m, p) → VolShellsRectangleSum((π * ((1 + (3 * y))^(2) - (1 + y^(2))^(2))), 0, (m * hy), m, p) → VolWashersSequence(Surface[-1 + ((1 + u) * cos(β)), ((k + 1) * hy), ((1 + u) * sin(β)), u, fI(((k + p) * hy)), gI(((k + p) * hy)), β, 0, α], k, 0, m - 1) → WashersBackSequence(Surface[-1 + ((1 + fI(((k + p) * hy))) * cos(β)), ((k + v) * hy), ((1 + fI(((k + p) * hy))) * sin(β)), v, 0, 1, β, 0, α], k, 0, m - 1) → WashInnersSequence(Surface[-1 + ((1 + (u * fI(((k + p) * hy))) + ((1 - u) * gI(((k + p) * hy)))) * cos(β)), ((k + u) * hy), ((1 + (u * fI(((k + p) * hy))) + ((1 - u) * gI(((k + p) * hy)))) * sin(β)), u, 0, 1, β, 0, α], k, 0, m - 1) → WasherFrontsSequence(Surface[-1 + ((1 + gI(((k + p) * hy))) * cos(β)), ((k + v) * hy), ((1 + gI(((k + p) * hy))) * sin(β)), v, 0, 1, β, 0, α], k, 0, m - 1) → WasherOutersSequence(Surface[-1 + ((1 + u) * cos(β)), f(((k + p) * hx)), ((1 + u) * sin(β)), u, (k * hx), ((k + 1) * hx), β, 0, α], k, 0, m - 1) → ShellsBackSequence(Surface[-1 + ((1 + u) * cos(β)), f(((k + p) * hx)), ((1 + u) * sin(β)), u, (k * hx), ((k + 1) * hx), β, 0, α], k, 0, m - 1) → ShellsFrontSequence(Surface[-1 + ((1 + (k * hx)) * cos(β)), (v * g(((k + p) * hx))) + ((1 - v) * f(((k + p) * hx))), ((1 + (k * hx)) * sin(β)), v, 0, 1, β, 0, α], k, 0, m - 1) → ShellsSidesLeftSequence(Surface[-1 + ((1 + ((k + 1) * hx)) * cos(β)), (v * g(((k + p) * hx))) + ((1 - v) * f(((k + p) * hx))), ((1 + ((k + 1) * hx)) * sin(β)), v, 0, 1, β, 0, α], k, 0, m - 1) → ShellsSidesRight