You are Here: Home >< Maths

# Integral of ln (sin x)

1. Hi,
Could some one tell me how to do the following indefinite integral

integral { ln (sin x) dx }

I thought I can do this by integration by parts. But it doesn't seem to work.

Thanks
2. I remembered seeing this before somewhere and Google was my friend.

http://community.boredofstudies.org/...ml#post3316947

and here:

http://mathforum.org/library/drmath/view/72243.html

You may struggle with an indefinite integral!!!
3. Isn't that the definite integral which is possible?

http://www.wolframalpha.com/input/?i...+ln%28sin+x%29
4. Yay for complex numbers.
5. ...umm damn I've completely forgotton all of C4...
6. (Original post by SimonM)
Isn't that the definite integral which is possible?

http://www.wolframalpha.com/input/?i...+ln%28sin+x%29
the 'polylogarithm function'?

I get dibs on the loganomial function
7. Let's not torture him:

http://math.ucsd.edu/~ebender/20B/7_DefInt.pdf
8. Similarly, try ...
9. Hi,
Thanks for every one who responded. I made a mistake. It was the improper integral, that I needed to find.

Actually the definite integral I needed to find is integral {ln (t*cos t) dt.}

I think I should be able to do it now with the above help.

Thanks for the help again.
10. Thanks for every one for the help. My problem is resolved.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: September 27, 2009
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### Need help with revision?

Check out our study tools and resources now.

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams