1. Express the integrand using the partial fractions found in part (a)
From part (a), we first find the partial fractions for x2(3x−2)3x2−4.
Let x2(3x−2)3x2−4=xA+x2B+3x−2C.
3x2−4=Ax(3x−2)+B(3x−2)+Cx2
Substituting x=0 gives −4=−2B⟹B=2.
Substituting x=32 gives 3(94)−4=C(94)⟹−38=94C⟹C=−6.
Comparing coefficients of x2 gives 3=3A+C⟹3=3A−6⟹A=3.
Thus, x2(3x−2)3x2−4=x3+x22−3x−26.
∫x2(3x−2)3x2−4dx=∫(x3+2x−2−3x−26)dx
2. Integrate each term using standard integration rules
=3lnx+−12x−1−36ln(3x−2)+c
=3lnx−x2−2ln(3x−2)+c
答案3lnx−x2−2ln(3x−2)+c