∫dx/(2-3x)(2x+1)
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/11/08 01:28:43
∫dx/(2-3x)(2x+1)
令1/[(2-3x)(2x+1)] = M/(2-3x) + N/(2x+1)
1 = M(2x+1) + N(2-3x)
代x = -1/2,1 = N(7/2) => N = 2/7
代x = 2/3,1 = M(7/3) => M = 3/7
∴∫ dx/[(2-3x)(2x+1)]
= (2/7)∫ dx/(2x+1) + (3/7)∫ dx/(2-3x)
= (2/7)(1/2)∫ d(2x+1)/(2x+1) + (3/7)(-1/3)∫ d(2-3x)/(2-3x)
= (1/7)ln|2x+1| - (1/7)ln|2-3x| + C
= (1/7)ln|(2x+1)/(2-3x)| + C
1 = M(2x+1) + N(2-3x)
代x = -1/2,1 = N(7/2) => N = 2/7
代x = 2/3,1 = M(7/3) => M = 3/7
∴∫ dx/[(2-3x)(2x+1)]
= (2/7)∫ dx/(2x+1) + (3/7)∫ dx/(2-3x)
= (2/7)(1/2)∫ d(2x+1)/(2x+1) + (3/7)(-1/3)∫ d(2-3x)/(2-3x)
= (1/7)ln|2x+1| - (1/7)ln|2-3x| + C
= (1/7)ln|(2x+1)/(2-3x)| + C