一般角的三角比自我评估
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①本范例演示了如何绘制和计算任意角度的三角比;②涉及的核心数学概念包括三角函数、参考角、一般角等;③作图要点使用了GeoGebra命令如Intersect, Angle, Segment, Polygon等;④适合高中数学教学和自学,用于理解和应用三角函数知识。
GeoGebra 命令及参数
Intersect(c, xAxis, 1) → CIntersect(c, xAxis, 2) → AIntersect(xAxis, yAxis) → OIf(m, θ_{debug}, If[counter < 11, (15 * Random[25, 48]), If[counter < 21, (5 * Random[73, 288]), (15 * Random[-48, -25])]]) → θ_{random}Angle(A, O, P) → ReferenceAngle1Angle(C, O, P) → ReferenceAngle2If(ReferenceAngle1 < 90.01°, ReferenceAngle1, ReferenceAngle2) → E3Angle(A, O, P) → α_+Segment(O, A) → aSegment(O, P) → bAngle(A, O, P_o) → θ_cAngle(P, O, A) → α_-Segment(O, C) → dIf(ReferenceAngle1 ≟ 0°, 1, floor((θ_o - 0.01) / 90) + 1) → nquadIf(Mod[nquad, 4] ≟ 0, 4, Mod[nquad, 4]) → quadElement(ListQuad, quad) → P_qPolygon(O, P, Q) → poly1, p_x, o, pAngle(O, Q, P) → rtAngledElement(ListGenAngle, quad) → P_gElement(ListRefAngle, quad) → P_fMidpoint(O, Q) → OQmidMidpoint(P, Q) → PQmidMidpoint(O, P) → OPmidAngle(A, O, P_o) → θ_{c2}Angle(A, O, P_o) → θ_{c3}Angle(A, O, P_o) → θ_{c4}Textfield(θ_o) → inputBox1If(α_+ ≟ 90° ∨ α_+ ≟ 270°, (θ_r + ((round(θ_r / π, 0) - 1) * π)) / 2, (θ_r + (round(θ_r / π, 0) * π)) / 2) → θ_tMidpoint(P_{rless20deg}, T_{basicangle}) → T_{genangle}Segment((x(C) - 0.3, y(C)), (x(A) + 0.3, y(A))) → xaxislineMirror(P_{xaxisarrow}, k) → P_{yaxisarrow}Mirror(xaxisline, k) → yaxislineIf(ReferenceAngle1 < 90.01°, ReferenceAngle1, ReferenceAngle2) → E4If(ReferenceAngle1 < 90.01°, ReferenceAngle1, ReferenceAngle2) → E5If(quad ≟ 1, "", If[quad ≟ 4, "", "-"]) → H4If(quad ≟ 1, "", If[quad ≟ 3, "", "-"]) → H5If(quad ≟ 1, "positive", If[quad ≟ 2, "positive", "negative"]) → G3If(quad ≟ 1, "positive", If[quad ≟ 4, "positive", "negative"]) → G4If(quad ≟ 1, "positive", If[quad ≟ 3, "positive", "negative"]) → G5If(abs(C3) ≟ 0, 0, If[C3 > 0, If[C3 - (floor(C3 / 360) * 360) ≟ 0, 360, C3 - (floor(C3 / 360) * 360)], If[abs(C3) - (floor(abs(C3) / 360) * 360) ≟ 0, 360, 360 - (abs(C3) - (floor(abs(C3) / 360) * 360))]]) → D3If(abs(C4) ≟ 0, 0, If[C4 > 0, If[C4 - (floor(C4 / 360) * 360) ≟ 0, 360, C4 - (floor(C4 / 360) * 360)], If[abs(C4) - (floor(abs(C4) / 360) * 360) ≟ 0, 360, 360 - (abs(C4) - (floor(abs(C4) / 360) * 360))]]) → D4If(abs(C5) ≟ 0, 0, If[C5 > 0, If[C5 - (floor(C5 / 360) * 360) ≟ 0, 360, C5 - (floor(C5 / 360) * 360)], If[abs(C5) - (floor(abs(C5) / 360) * 360) ≟ 0, 360, 360 - (abs(C5) - (floor(abs(C5) / 360) * 360))]]) → D5Random(1, 3) → selecttrigrationumIf(ReferenceAngle1 < 90.0100000000002°, ReferenceAngle1, ReferenceAngle2) → E1If(abs(C1) ≟ 0, 0, If[C1 > 0, If[C1 - (floor(C1 / 360) * 360) ≟ 0, 360, C1 - (floor(C1 / 360) * 360)], If[abs(C1) - (floor(abs(C1) / 360) * 360) ≟ 0, 360, 360 - (abs(C1) - (floor(abs(C1) / 360) * 360))]]) → D1Cell(7, 2 + selecttrigrationum) → G1If(quad ≟ 1, {J1, K1}, {J1, K1, L1, M1}) → listSelectedTrigChoicesRemove(listSelectedTrigChoices, {txtC1}) → listSelectedTrigChoices2Remove(listSelectedTrigChoices2, {txtC2}) → listSelectedTrigChoices3If(quad ≟ 1, {"Select", "a", "b"}, {"Select", "a", "b", "c", "d"}) → listAnswerChoiceIndexOf(Element[listShuffledChoices, SelectedIndex[listAnswerChoice]], listSelectedTrigChoices) → numListFeedbackTextfield(θ_{debug}) → InputBox1