圆锥表面积计算与展开
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①本范例演示圆锥的表面积计算公式及展开图;②涉及核心数学概念包括圆锥的底面积、侧面积、表面积公式、几何展开图;③作图要点:使用 GeoGebra 命令如 If, Conic, Segment, Midpoint, Point, Distance, Rotate, CircleSector, Polygon, Intersect, Arc, Circumference, Angle, CircumcircleArc, Textfield 等构建圆锥模型、计算参数并生成展开图;④适合高中阶段学生复习圆锥几何性质及表面积计算,也可用于几何直观教学。
GeoGebra 命令及参数
If(net < -1, (((-net) - 1) * 3), 0) → net_θIf(net < -1, (3 * ((-net) - 1)) + 0.2, 0.2) → net_bIf(net < -1, -1, net) → net_eIf(net_e > -0.001, 0, (-net_e)) → net_hConic(A, B, C, D, E) → cIf(net > 0, 1, 0) → net_1Conic(A, B, C, D, E) → dSegment(V, A') → bSegment(V, F') → eMidpoint(A', F') → M_{A'F'}Point(c) → GConic(A', B', C', F', E') → kConic(A', B', C', F', E') → pDistance(O, V) → distanceOVSegment(O_c, O_u) → lRotate(O_o, (θ * 2), V) → HRotate(O_o, ((-θ) * 2), V) → H'CircleSector(V, H', H) → qPolygon(V, A', F') → poly1, f', v, aDistance(V, H') → distanceVH'Segment(V, H) → b'Segment(V, H') → e'Intersect(p, b') → K, K_2Intersect(p, e') → J, J_2Segment(V, J_2) → gSegment(V, K_2) → iArc(p, A', K_2) → tArc(p, J_2, F') → fIf(θ + (0.6 * θ_d) < (((2 * π) * r / l_s) * 0.5), θ + (0.6 * θ_d), (((2 * π) * r / l_s) * 0.5)) → θ_cRotate(O_o, θ_c, V) → H_1Rotate(O_o, (-θ_c), V) → H'_1CircleSector(V, H'_1, H_1) → c_2Circumference(c_2) → jCircumference(c) → circumferencecDistance(V, H'_1) → distanceVH'1Angle(H'_1, V, H_1) → αPoint(c_2) → ICircumcircleArc(H', O_o, H) → c_1CircleSector(V, H'_1, H_1) → sSegment(M_{A'F'}, F') → mSegment(M_{A'F'}, V) → nAngle(F', M_{A'F'}, V) → βMidpoint(b) → M_{VA'}Textfield(r) → inputBox1Textfield(h) → inputBox2