∫dx/(x-2)平方(x-3)

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∫dx/(x-2)平方(x-3)

∫dx/(x-2)平方(x-3)
∫dx/(x-2)平方(x-3)

∫dx/(x-2)平方(x-3)
∫{1/[(x-2)^2(x-3)] } dx
1/[(x-2)^2(x-3)] = A/(x-2) +B/(x-2)^2 + C/(x-3)
=> 1 = A(x-2)(x-3) +B(x-3) +C(x-2)^2
coef.of x^2
A+C =0 (1)
put x=2
B=-1
coef.of constant
1= 6A-3B +4C
3A+2C = -1 (2)
(2)-2(1)
A = -1
C= 1
1/[(x-2)^2(x-3)] = -1/(x-2) -1/(x-2)^2 + 1/(x-3)
∫{1/[(x-2)^2(x-3)] } dx
= ∫(-1/(x-2) -1/(x-2)^2 + 1/(x-3)) dx
= -ln|x-2| + 1/(x-2) + ln|x-3| +C
= ln| (x-3)/(x-2) | +1/(x-2) +C

(x-3)/(x^2-3x+2)=A/(x-1)-B/(x-2) (x-3)/[(x-1)(x-2)]=A(x-2)/[(x-1)(x-2)-B(x-1)/[(x-1)(x-2)] (x-

令x-2=t, ∫dx/(x-2)平方(x-3)=∫(1/(t-1)-(t+1)/t^2)dt=ln(t-1)+1/t-lnt+c
然后带回即可