Integral - Algebraic Manipulation?

In summary, the process for solving the integral \int \frac{x}{x+d}dx involves rewriting the expression using the rule 1-1=\frac{x}{x+d}, and then using polynomial long division to simplify the expression. Alternatively, one can break the expression into smaller parts and integrate each part separately.
  • #1
Prologue
185
1

Homework Statement



[tex]\int \frac{x}{x+d}dx[/tex]

The Attempt at a Solution



I tried parts and that turned out horribly so I fired up maple. First move it makes is 'Rewrite Rule'. I've never heard of a rewrite rule but I supposed it could be some algebraic massaging. I ended up looking at it this way:

[tex]\frac{x}{x+d} = 1-1+\frac{x}{x+d} = \frac{x+d}{x+d}-\frac{x+d}{x+d}+\frac{x}{x+d} = \frac{x+d}{x+d}+\frac{x-d-x}{x+d} = 1-\frac{d}{x+d}[/tex]

Which then is easily integrable. My question is, is there a snappier way to think of this/do it?
 
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  • #2
Just divide x by x+d and you'll get the term on the rightmost of your equalities.
 
  • #3
As in polynomial long division?

edit: Or is there some way that is easy to see what will happen? Basically it isn't straight up intuitive for me to realize that x/x+d is 1-d/x+d, I'm trying to find a quick method to deal with it.
 
Last edited:
  • #4
[tex]\int\frac{x+d-d}{x+d}dx[/tex]

Break it and integrate.
 
  • #5
That's much shorter than what I did, thanks.
 

What is integral - algebraic manipulation?

Integral - algebraic manipulation is a method used in calculus to evaluate integrals involving algebraic expressions. It involves manipulating the algebraic expression to make the integral easier to solve.

What is the process of integral - algebraic manipulation?

The process of integral - algebraic manipulation involves using techniques such as substitution, integration by parts, and partial fractions to manipulate the algebraic expression in the integral. This manipulation typically results in a simpler integral that can be solved using basic integration rules.

Why is integral - algebraic manipulation useful?

Integral - algebraic manipulation is useful because it allows us to solve integrals that would otherwise be difficult or impossible to solve using basic integration rules. It also helps us to better understand the underlying algebraic structure of the integral.

What are some common techniques used in integral - algebraic manipulation?

Some common techniques used in integral - algebraic manipulation include integration by parts, substitution, partial fractions, and trigonometric identities. Each of these techniques is useful for manipulating specific types of algebraic expressions in integrals.

How can I improve my skills in integral - algebraic manipulation?

To improve your skills in integral - algebraic manipulation, it is important to practice and become familiar with the various techniques involved. You can also try solving a variety of integrals involving different types of algebraic expressions to gain a deeper understanding of the process.

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