<p>计算<img src="https://file.gaojiufeng.cn/learnAppQuestion/5f/57/5f577a0f1bfeb5eeca1b42f4aac2b29f.jpg" style="width: 100%;height: auto;">其中<img src="https://file.gaojiufeng.cn/learnAppQuestion/2a/d8/2ad8c44eaec4fbac992f0b4198a8637b.jpg" style="width: 100%;height: auto;">是由<img src="https://file.gaojiufeng.cn/learnAppQuestion/d9/9a/d99a688c9710ec02b40601dbfbbe987f.jpg" style="width: 100%;height: auto;">及<img src="https://file.gaojiufeng.cn/learnAppQuestion/19/88/198858305da6f61140ca0455faba762e.jpg" style="width: 100%;height: auto;">轴所围成的平面区域.</p>