题目
1.计算不定积分int(1)/(x^2)-3x+2dx.(6分)<|im_end|>请输入内容或上传图片...
1.计算不定积分$\int\frac{1}{x^{2}-3x+2}dx$.(6分)
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题目解答
答案
将被积函数分解为部分分式:
$\frac{1}{x^2 - 3x + 2} = \frac{1}{(x-1)(x-2)} = \frac{A}{x-1} + \frac{B}{x-2}$
解得 $A = -1$,$B = 1$,故
$\int \frac{1}{(x-1)(x-2)} \, dx = \int \left( \frac{1}{x-2} - \frac{1}{x-1} \right) \, dx$
分别积分得
$\ln |x-2| - \ln |x-1| + C = \ln \left| \frac{x-2}{x-1} \right| + C$
答案:
$\boxed{\ln \left| \frac{x-2}{x-1} \right| + C}$(或$\boxed{\ln |x-2| - \ln |x-1| + C}$)