三角函数加法公式演示
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①本范例通过动态图形演示三角函数加法公式;②涉及核心概念包括三角函数、角度、几何作图;③构造要点:使用 Circle, Point, Polygon, Line, OrthogonalLine, Intersect, Segment, CircleSector, Angle, If 等命令绘制图形并计算;④适合高中数学教学和几何作图学习。
GeoGebra 命令及参数
Circle(A, 1) → circlePoint(circle) → BPoint(circle) → DDPoint(circle) → DPolygon(A, B, C, D) → sinApB, a, b_2, c, dLine(A, DD) → redLotOrthogonalLine(D, redLot) → mOrthogonalLine(B, redLot) → nIntersect(m, redLot) → MIntersect(n, redLot) → NLine(A, B) → greenLotLine(M, greenLot) → parallelSegment(B, N) → redHoeheIntersect(Line[C, Vector[D, M]], parallel) → EPolygon(M, E, C, D) → sinAcosB, e, f, g, hPolygon(M, A, B, E) → cosAsinB, m_1, a_1, b_1, e_1Segment(D, Intersect[OrthogonalLine[D, greenLot], greenLot]) → greenHoeheIntersect(redLot, Line[C, E]) → CESegment(M, CE) → blueHoeheLine(C, E) → blueLotSegment(B, E) → redGrund_1Segment(C, E) → blueGrund_1Segment(A, M) → redGrund_2Segment(D, M) → blueGrund_2Segment(A, B) → greenGrund_1Segment(C, D) → greenGrund_2Intersect(circle, Ray[A, Midpoint[Segment[B, DD]]]) → mBDD,Intersect(circle, Ray[A, Midpoint[Segment[D, DD]]]) → mBD,CircleSector(A, DD / 5, D / 5) → angACircleSector(A, B / 5, DD / 5) → angBAngle(D, A, DD) → alIf(al > 180°, (0.1 * mBD), ((-0.1) * mBD)) → PalphaAngle(DD, A, B) → blIf(bl > 180°, (0.1 * mBDD), ((-0.1) * mBDD)) → Pbeta