Simplify using partial fractions: Step 1: Simplify the integral using partial fractions.We start by expressing the denominator as a sum of simpler fractions:x3+1 can be factored as (x+1)(x2−x+1).Now, we set up the partial fractions:x3+11=x+1A+x2−x+1Bx+C.
Solve for A, B, C: Step 2: Solve for A, B, and C.Multiply through by x3+1 to clear the denominators:1=A(x2−x+1)+(Bx+C)(x+1).Expanding and equating coefficients, we get:1=Ax2−Ax+A+Bx2+Bx+Cx+C.Equating coefficients:For x2: A+B=0,For x: −A+B+C=0,For constant: A+C=1.
Solve system of equations: Step 3: Solve the system of equations.From A+B=0, we get B=−A.Substituting B=−A into −A+B+C=0 gives −A−A+C=0, so C=2A.Substituting C=2A into A+C=1 gives A+2A=1, so A=31.Then, B=−A0, and B=−A1.
Write integral with coefficients: Step 4: Write the integral with the found coefficients.The integral becomes:\int(\(1/(x^3 + 1))\,dx = \int(\frac{1}{3})/(x + 1)\,dx + \int(\frac{−1}{3x} + \frac{2}{3})/(x^2 - x + 1)\,dx.
Integrate each term: Step 5: Integrate each term.For ∫31x+11dx, the integral is 31ln∣x+1∣.For ∫x2−x+1−31x+32dx, we need to complete the square in the denominator:x2−x+1=(x−21)2+43.The integral becomes more complex and involves a substitution and possibly trigonometric integration.
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