- #1

- 23

- 0

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

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- Thread starter desmal
- Start date

- #1

- 23

- 0

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

- #2

- 8

- 1

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

- 0

Wow really really amazing

Unfortunately, there is something puzzling me which is:-

How did you get the idea of substituting u=tan(x/2)

- #4

HallsofIvy

Science Advisor

Homework Helper

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Actually, "u= tan(x/2)" is a common substitution method. Check this:

http://en.wikipedia.org/wiki/Tangent_half-angle_formula

- #5

Cyosis

Homework Helper

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- 0

nikkor180 said:

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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