1. ## Integration help

Ok, I am trying to integrate the following function, and not getting very far: it's s=integral between 0 and 2pi of cos^-1(arctan((2*pi/b)*a*cos(2*pi*x/b)))dx)^-1 where a and b are known variables. What I would like to know, is can this integral be evaluated directly, or must I use the trapezium rule, and if so how would I do that?

2. Originally Posted by jamie516
Ok, I am trying to integrate the following function, and not getting very far: it's s=integral between 0 and 2pi of cos^-1(arctan((2*pi/b)*a*cos(2*pi*x/b)))dx)^-1 where a and b are known variables. What I would like to know, is can this integral be evaluated directly, or must I use the trapezium rule, and if so how would I do that?
What is the exact wording of the question? What context does it come from?

3. It isn't a question as such, I need to get an efficiency factor for a wavy carbon fibre, part of the equation for which is that equation. a and b are known constants not variables by the way.

4. Originally Posted by jamie516
It isn't a question as such, I need to get an efficiency factor for a wavy carbon fibre, part of the equation for which is that equation. a and b are known constants not variables by the way.
Then I'd suggest using a numerical method (ie. technology) to get an answer to a desired accuracy.

5. Yes, I'm trying to do that in Excel, my problem is that I can't seem to do it.

6. Originally Posted by jamie516
Yes, I'm trying to do that in Excel, my problem is that I can't seem to do it.
Well then, as it stands there's not much can be done to diagnose your problem. Perhaps if you give the values of a and b someone might find time to get the answer.

7. Ok then well a and b can change the shape of the sine wave for wavy fibres, so for instance a could be =2 and b could be =1.1, i can change them to be anything I want.