Integral - Algebraic Manipulation?

Join the discussion
Ask a follow-up here, or get your own question answered by working scientists, mathematicians and engineers — people, not an autocomplete.
Real named experts · corrections over time · the nuance an AI answer skips
4 replies · 3K views
Prologue
Messages
183
Reaction score
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?
 
Physics news on Phys.org
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:
[tex]\int\frac{x+d-d}{x+d}dx[/tex]

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