1. Determine the constants $A$ and $B$ by comparing coefficients.
x=A(8x−8)+B
x=8Ax−8A+B
Comparing the coefficients of x:
8A=1⟹A=81
Comparing the constant terms:
−8A+B=0
−8(81)+B=0⟹B=1
2. Rewrite the integral by splitting it into two parts using the partial numerator.
Substitute A and B back into the integrand:
∫014x2−8x+5xdx=∫014x2−8x+581(8x−8)+1dx
=81∫014x2−8x+58x−8dx+∫014x2−8x+51dx
3. Evaluate the first integral using the standard form $\int \frac{\mathrm{f}'(x)}{\mathrm{f}(x)} \,\text{d}x$.
81∫014x2−8x+58x−8dx=81[ln∣4x2−8x+5∣]01
=81(ln(4(1)2−8(1)+5)−ln(4(0)2−8(0)+5))
=81(ln1−ln5)=−81ln5
4. Complete the square for the denominator of the second integral.
4x2−8x+5=4(x2−2x)+5
=4(x2−2x+1)−4+5
=4(x−1)2+1
5. Evaluate the second integral using the standard form $\int \frac{1}{x^2 + a^2} \,\text{d}x$ and combine.
∫014(x−1)2+11dx=41∫01(x−1)2+(21)21dx
=41[211tan−1(21x−1)]01=21[tan−1(2x−2)]01
=21(tan−1(0)−tan−1(−2))
Since tan−1(−x)=−tan−1(x), we have:
=21(0−(−tan−12))=21tan−12
Combining both parts:
∫014x2−8x+5xdx=−81ln5+21tan−12
Answer-\frac{1}{8} \ln 5 + \frac{1}{2} \tan^{-1} 2