Integrating with partial fractions and simpifying the answer

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SUMMARY

The discussion focuses on solving the definite integral of (x-1)/(x^3+4x^2+3x) from x=1 to x=3 using partial fraction decomposition. The correct antiderivative is confirmed to be -(1/3)ln(x) - (2/3)ln(x+3) + ln(x+1). Participants emphasize the importance of simplifying logarithmic expressions, specifically using properties such as ln(6) = ln(2) + ln(3) and ln(4) = 2ln(2) to arrive at the final answer of (5/3)ln2 - ln3.

PREREQUISITES
  • Understanding of definite integrals
  • Familiarity with partial fraction decomposition
  • Knowledge of logarithmic properties
  • Basic calculus skills
NEXT STEPS
  • Study techniques for simplifying logarithmic expressions
  • Learn more about partial fraction decomposition in calculus
  • Explore advanced integration techniques, including integration by parts
  • Review properties of logarithms and their applications in calculus
USEFUL FOR

Students studying calculus, particularly those focusing on integration techniques and logarithmic simplification, as well as educators teaching these concepts.

tasveerk
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Homework Statement


the definite integral of (x-1)/(x^3+4x^2+3x) from x=1 to x=3 using partial fraction decomposition. I know the answer should be (5/3)ln2 - ln3.


Homework Equations





The Attempt at a Solution


After integrating, I got -(1/3)ln(3x) - (2/3)ln(x+3) + ln(x+1) . The issue is that after I implement the limits of integration, I cannot seem to simplify it to get the answer (5/3)ln2 - ln3.
 
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I believe your -(1/3)ln(3x) should be -(1/3)ln(x)
 
tasveerk said:
After integrating, I got -(1/3)ln(x) - (2/3)ln(x+3) + ln(x+1) .

I agree with your result for the antiderivative (after fixing that "3x" ). One of the terms in the evaluation gives (1/3) ln 1 and so can be omitted. Be sure to consider that ln (6) = ln (2) + ln (3) and that ln ( 4 ) = 2 ln ( 2 ) . The stated answer appears to be correct.
 

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