Integration [ 1/(c+cos(x)) ] by dx

  • Thread starter desmal
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  • #1
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Main Question or Discussion Point

Hi all

Can you solve the following integration: -

Integration [ cos(x)/(c+cos(x)) ] by dx
where c is a constant

or that one: -

Integration [ 1/(c+cos(x)) ] by dx

if one is solved I will be able to make the other
 

Answers and Replies

  • #2
8
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Greetings:

If you let u = tan(x/2), then dx = 2*du /(u^2+1), sin(x) = 2u/(u^2+1), cos(x) = (1-u^2)/(1+u^2). If you substitute these values appropriately, each integral should return an inverse trig function.

Regards,

Rich B.
 
  • #3
23
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Wow really really amazing

Unfortunately, there is something puzzling me which is:-
How did you get the idea of substituting u=tan(x/2)
 
  • #5
Cyosis
Homework Helper
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nikkor180 said:
Wow really really amazing

Unfortunately, there is something puzzling me which is:-
How did you get the idea of substituting u=tan(x/2)
There is no clear cut method to finding primitives. It's much like puzzling, try something out and remember what works.
 

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