Integrals of the Form $\int\dfrac{px+q}{ax^2+bx+c}\,dx$ and $\int\dfrac{px+q}{\sqrt{ax^2+bx+c}}\,dx$
10.2.7
Integrals of the Form $\int\dfrac{px+q}{ax^2+bx+c}\,dx$ and $\int\dfrac{px+q}{\sqrt{ax^2+bx+c}}\,dx$
When the numerator is linear, write px+q=A⋅dxd(ax2+bx+c)+B for constants A,B found by comparing coefficients. This splits ∫ax2+bx+cpx+qdx into A∫ax2+bx+cdxd(ax2+bx+c)dx+B∫ax2+bx+cdx — the first piece is a Corollary-III log (put ax2+bx+c=t), the second is the 3.2.4 type. Exactly the same split works for ∫ax2+bx+cpx+qdx, with the first piece becoming a Corollary-IV square root instead of a log.
∫3x2+4x+52x−3dx. Write 2x−3=A(6x+4)+B; comparing coefficients, 6A=2⇒A=31, and 4A+B=−3⇒B=−313. So I=31∫3x2+4x+56x+4dx−313∫3x2+4x+5dx=31log(3x2+4x+5)−31113tan−1113x+2+c (the second integral evaluated by completing the square, 3.2.4-style).
∫x−7x−5dx. Multiply inside the root by x−5x−5: the integrand becomes (x−5)(x−7)x−5=x2−12x+35x−5. Write x−5=21(2x−12)+1: this splits into 21∫x2−12x+352x−12dx+∫x2−12x+35dx. The first is a Corollary-IV square root, x2−12x+35; the second, after completing the square to (x−6)2−1, is a Formula-5 log. Result: I=x2−12x+35+log(x−6)+x2−12x+35+c. …