Question

11．如图所示的阴影部分可用二元一次不等式组表示为$\left\{\begin{array}{l}{x-y≥0}\\{x+y＞0}\end{array}\right.$或$\left\{\begin{array}{l}{x-y≤0}\\{x+y＞0}\end{array}\right.$．

Answer 1

分析 根据不等式组表示平面区域，即可确定阴影部分的对应的不等式组．

解答 解：由图象可知阴影部分在直线y=x的下方，直线y=-x的上方，或在直线y=x的上方，直线y=-x的下方
∴对应的不等式组为$\left\{\begin{array}{l}{y≥x}\\{y＜-x}\end{array}\right.$或$\left\{\begin{array}{l}{y≥x}\\{y＜-x}\end{array}\right.$，即$\left\{\begin{array}{l}{x-y≥0}\\{x+y＞0}\end{array}\right.$或$\left\{\begin{array}{l}{x-y≤0}\\{x+y＞0}\end{array}\right.$，
故答案为：$\left\{\begin{array}{l}{x-y≥0}\\{x+y＞0}\end{array}\right.$或$\left\{\begin{array}{l}{x-y≤0}\\{x+y＞0}\end{array}\right.$．

点评 本题主要考查二元一次不等式组表示平面区域，比较基础．