单位圆三角函数 by Sally Booth
几何画板及绘图内容加载中,请稍等……
①本范例演示单位圆上角度与三角函数值(sin, cos)的对应关系;②涉及核心数学概念为单位圆、三角函数、角度测量;③作图要点运用了Circle, Rotate, Angle, Intersect, OrthogonalLine, Polygon, Ray等GeoGebra命令及对象O, c, θ, x, B, δ等;④适合高中数学教学和学生理解三角函数定义。
GeoGebra 命令及参数
Intersect(xAxis, yAxis) → OCircle(O, 1) → cRotate(x_1, θ_1, O) → B_1Angle(x_1, O, B_1) → δ_1OrthogonalLine(B_1, xAxis) → fIntersect(f, xAxis) → C_1Polygon(O, B_1, C_1) → t1, c_1, o, bRotate(x_1, θ_2, O) → B_2Angle(x_1, O, B_2) → δ_2OrthogonalLine(B_2, xAxis) → gIntersect(g, xAxis) → C_2Polygon(O, B_2, C_2) → t2, c_2, o_1, b_2Angle(C_1, O, B_1) → ϕ_1Angle(B_2, O, C_2) → ϕ_2Rotate(C_1, θ_3, O) → BAngle(C_1, O, B) → δ_3Ray(O, B) → hIntersect(c, h) → B_3,OrthogonalLine(B_3, xAxis) → iIntersect(i, xAxis) → C_3Polygon(O, B_3, C_3) → t3, c_3, o_2, b_3Angle(C_3, O, B_3) → ϕ_3Rotate(C_1, θ_4, O) → AAngle(C_1, O, A) → δ_4Ray(O, A) → jIntersect(c, j) → B_4,OrthogonalLine(B_4, xAxis) → kIntersect(k, xAxis) → C_4Polygon(O, B_4, C_4) → t4, c_4, o_3, b_4Angle(B_4, O, C_4) → ϕ_4