Rewrite Integral: Rewrite the integral by factoring the denominator and simplifying the expression.Denominator: (x2−x)(x2+4)=x(x−1)(x2+4).Attempt partial fraction decomposition:Let x(x−1)(x2+4)2x3−4x−8=xA+x−1B+x2+4Cx+D.Multiply through by the denominator to clear fractions:2x3−4x−8=A(x−1)(x2+4)+Bx(x2+4)+(Cx+D)x(x−1).
Partial Fraction Decomposition: Expand and equate coefficients for x3, x2, x, and constant terms.Expanding:A(x3−x2+4x−4)+B(x3+4x)+Cx2(x−1)+Dx(x−1)= Ax3−Ax2+4Ax−4A+Bx3+4Bx+Cx3−Cx2+Dx2−Dx.Combine like terms and equate to the original polynomial:(A+B+C)x3+(−A−C+D)x2+(4A+4B−D)x−4A=2x3−4x−8.
Expand and Equate Coefficients: Solve the system of equations for A, B, C, D:1. A+B+C=2,2. −A−C+D=0,3. 4A+4B−D=−4,4. −4A=−8.From equation 4, A=2.Substitute A into other equations and solve for B, C, D.
Solve System of Equations: Substituting A=2 into equations:1. 2+B+C=2, B+C=0,2. −2−C+D=0, D=2+C,3. 8+4B−D=−4.Substitute D=2+C into equation 3:8+4B−(2+C)=−4,4B−C=−10.
Solve for B and C: Solve B+C=0 and 4B−C=−10 simultaneously:From B+C=0, C=−B.Substitute C=−B into 4B−C=−10:4B+B=−10,5B=−10,C0.Then C1.
Find D: Find D using D=2+C: D=2+2=4. Now we have A=2, B=−2, C=2, D=4. The partial fractions are: x2−x−12+x2+42x+4.
Integrate Each Term: Integrate each term separately:∫x2dx=2ln∣x∣+C1,∫x−1−2dx=−2ln∣x−1∣+C2,∫x2+42x+4dx=ln(x2+4)+4arctan(2x)+C3.Combine constants: C=C1+C2+C3.
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