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how to solve for the integral of 1 over the cos(x) + 1?
Hey again, so to write it, out it is:
S(1/cos(x) + 1) dx The 'S' is my integral sign.
Anyone?
4 Answers
- supersonic332003Lv 71 decade agoFavorite Answer
Use the identity (cosx+1)/2=cos^2(x/2).
Then S=Sdx/[2cos^2(x/2)]=S(1/cos^2(x/2)) d(x/2)=tan(x/2)
The simplest you can get!!!
- ComoLv 71 decade ago
â«(1/cos x )+ 1dx = â« sec x dx + x + C
= log(sec x + tan x) + x + C
Note that the integral of sec x is a standard integral, log(sec x + tan x)
- BugmänLv 41 decade ago
I would multiply 1/(cosx + 1) by (cosx -1)/(cosx - 1).
Then you will have
(cosx - 1)/(cos²x - 1),
(cosx - 1)/(-sin²x),
(-cosx)/(sin²x) + (1)/(sin²x),
-cotxcscx + csc²x.
The derivative of cscx is -cotxcscx and the derivative of cotx is csc²x.
Feel free to email me for further clarifications.
- NorthstarLv 71 decade ago
I assume you mean 1/(cos(x) + 1).
First let's rearrange the terms to make it easier to integrate.
1/(cos(x) + 1) = 1/[1 + cos(x)]
= [1 - cos(x)]/{[1 + cos(x)][1 - cos(x)]}
= [1 - cos(x)]/[1 - cos²(x)] = [1 - cos(x)]/sin²(x)
= 1/sin²(x) - cos(x)/sin²(x) = csc²(x) - (cot(x))(csc(x))
Now we can integrate.
â«1/(cos(x) + 1)dx = â«{csc²(x) - (cot(x))(csc(x))}dx
= -cot(x) + csc(x) + C