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Learn how to decompose algebraic fractions for easier integration, step-by-step strategies, variations, and examples for tackling complex polynomials. Enhance your integration skills with practical exercises.
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Partial Fractions Lesson 8.5
Partial Fraction Decomposition • Consider adding two algebraic fractions • Partial fraction decomposition reverses the process
Partial Fraction Decomposition • Motivation for this process • The separate terms are easier to integrate
The Process • Given • Where polynomial P(x) has degree < n • P(r) ≠ 0 • Then f(x) can be decomposed with this cascading form
Strategy Given N(x)/D(x) • If degree of N(x) greater than degree of D(x) divide the denominator into the numerator to obtainDegree of N1(x) will be less than that of D(x) • Now proceed with following steps for N1(x)/D(x)
Strategy • Factor the denominator into factors of the formwhere is irreducible • For each factor the partial fraction must include the following sum of m fractions
Strategy • Quadratic factors: For each factor of the form , the partial fraction decomposition must include the following sum of n fractions.
A Variation • Suppose rational function has distinct linear factors • Then we know
A Variation • Now multiply through by the denominator to clear them from the equation • Let x = 1 and x = -1 • Solve for A and B
What If • Single irreducible quadratic factor • But P(x) degree < 2m • Then cascading form is
Gotta Try It • Given • Then
Gotta Try It • Now equate corresponding coefficients on each side • Solve for A, B, C, and D ?
Even More Exciting • When but • P(x) and D(x) are polynomials with no common factors • D(x) ≠ 0 • Example
Combine the Methods • Consider where • P(x), D(x) have no common factors • D(x) ≠ 0 • Express as cascading functions of
Try It This Time • Given • Now manipulate the expression to determine A, B, and C
Partial Fractions for Integration • Use these principles for the following integrals
Why Are We Doing This? • Remember, the whole idea is tomake the rational function easier to integrate
Assignment • Lesson 8.5 • Page 559 • Exercises 1 – 29 EOO