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CIE 9709 2026 June Paper 12 Q2

A Level / CIE / P1

CIE 9709 2026 June Paper 12 Paper · Question 2

题目

Problem

In the diagram, the graph with equation y=f(x)y=\mathrm{f}(x) is shown with solid lines and the graph with equation y=g(x)y=\mathrm{g}(x) is shown with broken lines.

(a) Describe fully a sequence of transformations which transforms the graph of y=f(x)y=\mathrm{f}(x) to the graph of y=g(x)y=\mathrm{g}(x). You should make clear the order in which the transformations are applied.

(5)

(b) Find an expression for g(x)\mathrm{g}(x) in the form af(x+b)+ca\mathrm{f}(x+b)+c, where aa, bb and cc are constants.

(2)
题目中文翻译

图中,方程为 y=f(x)y=\mathrm{f}(x) 的图像用实线表示,方程为 y=g(x)y=\mathrm{g}(x) 的图像用虚线表示。

(a) 完整描述一组将 y=f(x)y=\mathrm{f}(x) 的图像变为 y=g(x)y=\mathrm{g}(x) 的图像的变换,并清楚说明这些变换的先后顺序。

(5)

(b) 求 g(x)\mathrm{g}(x) 的表达式,写成 af(x+b)+ca\mathrm{f}(x+b)+c 的形式,其中 aa、bb 和 cc 为常数。

(2)
原卷通用作答要求

Answer all questions. You should use a calculator where appropriate.

You must show all necessary working clearly; no marks will be given for unsupported answers from a calculator.

Give non-exact numerical answers correct to 3 significant figures, or 1 decimal place for angles in degrees, unless a different level of accuracy is specified in the question.

请回答所有题目。适当时应使用计算器。必须清楚展示所有必要的计算过程;仅给出计算器答案而没有过程,不予评分。除非题目另有精度要求,非精确数值答案保留 3 位有效数字,以度为单位的角度保留 1 位小数。

解答

(a)

解法一

思路

展开

对应点都右移 11。实线的高度差 66 变成虚线的高度差 33,所以纵坐标先缩为一半,再补足整体高度。

答题过程

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The points (0,−10)(0,-10) and (2,−4)(2,-4) map to (1,0)(1,0) and (3,3)(3,3). First stretch by scale factor 1/21/2 in the yy-direction, then translate by (15)\begin{pmatrix}1\\5\end{pmatrix}. This sends (x,y)(x,y) to (x+1,y/2+5)(x+1,y/2+5).

解法二

思路

展开

若先平移,纵向位移也会缩为一半,因此先上移 1010。

答题过程

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First translate by (110)\begin{pmatrix}1\\10\end{pmatrix}, then stretch by scale factor 1/21/2 in the yy-direction. The resulting point is (x+1,(y+10)/2)(x+1,(y+10)/2), which gives the required image.

(b)

解法一

思路

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新横坐标是原横坐标加 11,所以要用 x−1x-1 查回原高度。

答题过程

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At a new coordinate xx, the old height is f(x−1)f(x-1). Applying the vertical scale and shift gives

g(x)=12f(x−1)+5.g(x)=\frac12f(x-1)+5.

Thus a=1/2a=1/2, b=−1b=-1 and c=5c=5.