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∫[(x-3)/(x-1)(x²-1)]dx=∫(x-3)/(x-1)²(x+1)]dx;
将被积函数进行拆项:(x-3)/(x-1)²(x+1)]=[(ax+b)/(x-1)²]+c/(x+1)[下面通分]
=[(ax+b)(x+1)+c(x-1)²]/[(x-1)²(x+1)]=[ax²+(a+b)x+b+cx²-2cx+c]/[(x-1)²(x+1)]
=[(a+c)x²+(a+b-2c)x+(b+c)]/[(x-1)²(x+1)][因为是恒等变换,两边对应项的系数应该相等]
因此有方程组:a+c=0........①;a+b-2c=1...........②;b+c=-3...........③
三式联立求解:①+③得a+b+2c=-3........④;④-②得:4c=-4,∴c=-1;a=1,b=-2;
∴∫[(x-3)/(x-1)(x²-1)]dx=∫[(x-2)/(x-1)²]dx-∫[1/(x+1)]dx
=∫[(x-2)/(x²-2x+1)]dx-∫[1/(x+1)]d(x+1)
=(1/2)∫[(2x-2)/(x²-2x+1)]dx-∫[1/(x-1)²]d(x-1)-∫[1/(x+1)]d(x+1)
=(1/2)∫d(x²-2x+1)/(x²-2x+1)-∫d(x-1)/(x-1)²-∫[1/(x+1)]d(x+1)
=(1/2)ln∣x²-2x+1∣+[1/(x-1)]-ln∣x+1∣+C
=ln∣(x-1)/(x+1)∣+[1/(x-1)]+C;
将被积函数进行拆项:(x-3)/(x-1)²(x+1)]=[(ax+b)/(x-1)²]+c/(x+1)[下面通分]
=[(ax+b)(x+1)+c(x-1)²]/[(x-1)²(x+1)]=[ax²+(a+b)x+b+cx²-2cx+c]/[(x-1)²(x+1)]
=[(a+c)x²+(a+b-2c)x+(b+c)]/[(x-1)²(x+1)][因为是恒等变换,两边对应项的系数应该相等]
因此有方程组:a+c=0........①;a+b-2c=1...........②;b+c=-3...........③
三式联立求解:①+③得a+b+2c=-3........④;④-②得:4c=-4,∴c=-1;a=1,b=-2;
∴∫[(x-3)/(x-1)(x²-1)]dx=∫[(x-2)/(x-1)²]dx-∫[1/(x+1)]dx
=∫[(x-2)/(x²-2x+1)]dx-∫[1/(x+1)]d(x+1)
=(1/2)∫[(2x-2)/(x²-2x+1)]dx-∫[1/(x-1)²]d(x-1)-∫[1/(x+1)]d(x+1)
=(1/2)∫d(x²-2x+1)/(x²-2x+1)-∫d(x-1)/(x-1)²-∫[1/(x+1)]d(x+1)
=(1/2)ln∣x²-2x+1∣+[1/(x-1)]-ln∣x+1∣+C
=ln∣(x-1)/(x+1)∣+[1/(x-1)]+C;
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那个杭绣的要求是可以求解的,具体的你可以考虑一下
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高效有理函数的积分怎么求?当然是按照他的定理方式来做,按照勾选和CN的具体标准来做
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