CAJ | 학술논문

当积分区域具有对称性,被积函数具有奇偶性时,可以简化二重积分的计算过程.给出并证明了积分区域关于一个坐标轴对称、关于两个坐标轴都对称、被积函数具有某种特性的二重积分计算公式,进而给出积分区域关于任意直线对称的二重积分的计算公式;举例说明了各类重积分计算公式的应用.
당적분구역구유대칭성,피적함수구유기우성시,가이간화이중적분적계산과정.급출병증명료적분구역관우일개좌표축대칭、관우량개좌표축도대칭、피적함수구유모충특성적이중적분계산공식,진이급출적분구역관우임의직선대칭적이중적분적계산공식;거례설명료각류중적분계산공식적응용.
When a comprehensive evaluation on Hengshui Lake, a large water environment, is carded out, it will involve a lot of complex phenomena and the interaction of various complicated factors. There are plenty of fuzzy phenomena and fuzzy concept. The article chooses five indexes of seven measure points as evaluating factors. They are dissolved oxygen, ammonia nitrogen, total phosphorus, total nitrogen and potassium permanganate. The pollution level of each point is calculated with the fuzzy comprehensive evaluation method. The results show that, when The National Standards of Surface Water Environment Quality is referred to, Point 1, Point 3, Point 5 and Point 6 are in line with the national standard, while Point 2, Point 4 and Point 7 are not conform to the national standard. Therefore, the management of the waters of Point 2, Point 4 and Point 7 should be strengthened; the treatment of pollutants should be reinforced and the water quality of the environment should be improved.