Partial fraction decomposition

In summary, partial fraction decomposition is a mathematical technique used to break down a rational function into simpler fractions by factoring the denominator and determining the individual fractions that make up the original function. It is commonly used in integration, solving systems of linear equations, and in engineering and physics applications. The process involves writing a fraction for each distinct factor of the denominator and solving a system of equations to determine the numerators. There are two types of partial fraction decomposition: proper and improper. Some tips for solving these problems include factoring the denominator completely, keeping track of constants in the numerators, and checking the final solution.
  • #1
Jordan1994
4
0
Q3.) Express as partial fractions.

a) \(\displaystyle \frac{3x+4}{x^2+3x+2}\)

b) \(\displaystyle \frac{5x^2+5x+8}{(x+2)\left(x^2+2 \right)}\)

c) \(\displaystyle \frac{x^2+15x+21}{(x+2)^2(x-3)}\)
 
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  • #2
Let's begin with a). Can you state the form the partial fraction will take?
 
  • #3
Here's a) without the full method:

\(\displaystyle \begin{align*}
\frac{3x+4}{{{x}^{2}}+3x+2}&=\frac{3x+4}{(x+1)(x+2)} \\
& =\frac{2x+2+x+2}{(x+1)(x+2)} \\
& =\frac{2(x+1)+x+2}{(x+1)(x+2)} \\
& =\frac{2}{x+2}+\frac{1}{x+1}. \\
\end{align*}\)
 

FAQ: Partial fraction decomposition

What is partial fraction decomposition?

Partial fraction decomposition is a mathematical technique used to break down a rational function into simpler fractions. It involves determining the individual fractions that, when combined, make up the original function.

When is partial fraction decomposition used?

Partial fraction decomposition is commonly used in integration, as it can simplify the integration process by breaking down complex fractions into more manageable ones. It is also used in solving systems of linear equations and in some engineering and physics applications.

How is partial fraction decomposition done?

The process of partial fraction decomposition involves first factoring the denominator of the rational function. Then, for each distinct factor, a fraction with that factor as its denominator is written. The numerator of each fraction is determined by solving a system of equations using the original function and the fractions written so far.

What are the types of partial fraction decomposition?

There are two types of partial fraction decomposition: proper and improper. In proper decomposition, the degrees of the numerators are all less than the degree of the denominator. In improper decomposition, at least one of the numerators has a degree equal to or greater than the degree of the denominator.

What are some tips for solving partial fraction decomposition problems?

One tip is to always start by factoring the denominator completely before writing the fractions. Another is to keep track of the constants in the numerators while solving the system of equations to avoid mistakes. It is also important to check the final solution by adding the fractions back together to make sure it equals the original function.

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