题目
On a sketch of an Argand diagram, shade the region whose points represent complex numbers satisfying the inequalities and .
题目中文翻译
在阿根图的草图上,用阴影表示满足不等式 和 的复数 所对应的点组成的区域。
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
解法一
思路
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模条件给出圆心 、半径 的闭圆盘。整个圆盘在上半平面,辐角条件因此选择射线 的顺时针一侧。
答题过程
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Write . The first condition gives
Draw this circle, with centre and radius .
The boundary is the ray from the origin through the second quadrant along .
The disc lies entirely above the real axis. Therefore the condition selects points with . Shade the intersection of this half-plane and the disc, including both boundaries.