Câu 7:
Biết ∫12xdx(x+1)(2x+1)=aln2+bln3+cln5\int\limits_1^2 {\dfrac{{xdx}}{{\left( {x + 1} \right)\left( {2x + 1} \right)}} = a\ln 2 + b\ln 3 + c\ln 5}1∫2(x+1)(2x+1)xdx=aln2+bln3+cln5. Tính S=a+b+cS = a + b + cS=a+b+c
