(1/4)(5x+3)/(x^2-2x+5)^2 = (1/4)(5x-5+8)/(x^2-2x+5)^2= (5/4)(x-1)/(x^2-2x+5)^2 + 2/(x^2-2x+5)^2 = (5/8)(2x-2)/(x^2-2x+5)^2 + 2/(x^2-2x+5)^2
不定积分这一步怎么退呢？不定积分，根据分部积分法。凑并分法来解决不定积分的计算
