trig integral

• Apr 24th 2009, 03:05 PM
alex83
trig integral
integral
dx/[(sin x)(cos x)]

how do i approach such an example
• Apr 24th 2009, 03:08 PM
Jester
Quote:

Originally Posted by alex83
integral
dx/[(sin x)(cos x)]

how do i approach such an example

$\displaystyle \frac{1}{\sin x \cos x} = \frac{2}{\sin 2x} = 2 \csc 2x$ and

$\displaystyle 2 \int \csc 2x\, dx$ is a standard integral (if $\displaystyle u = 2x$).
• Apr 24th 2009, 03:14 PM
Jameson
alex83 - Once again I'm going to ask that you show some effort before making another thread on trig integral problems. It seems you are going down the list of your homework. We want you to learn how to do these on your own and it doesn't seem you know how to.
• Apr 24th 2009, 03:14 PM
mr fantastic
Quote:

Originally Posted by alex83
integral
dx/[(sin x)(cos x)]

how do i approach such an example

sin x cos x can be re-written as 0.5 sin (2x). So your job is to integrate a cosec function. See here: http://www.mathhelpforum.com/math-he...barrassed.html

You will not get any further help on this question until you show your working and state where you get stuck. You may not think so, but this is actually for your own academic benefit. Maths is not a spectator sport.
• Apr 24th 2009, 03:31 PM
alex83
Quote:

Originally Posted by Jameson
alex83 - Once again I'm going to ask that you show some effort before making another thread on trig integral problems. It seems you are going down the list of your homework. We want you to learn how to do these on your own and it doesn't seem you know how to.

actually im studying for my finals and i have my solution manual with me but when the book shows an answer differnet than mine and i dont understand the way they got to a certain step i seek help from this helpful forum which i learned from more than my class..

thank you anyway but pls. dont get me wrong
• Apr 24th 2009, 03:35 PM
mr fantastic
Quote:

Originally Posted by alex83
actually im studying for my finals and i have my solution manual with me but when the book shows an answer differnet than mine and i dont understand the way they got to a certain step i seek help from this helpful forum which i learned from more than my class..

thank you anyway but pls. dont get me wrong

If that happens you should post the solution you've been given and say what part of it you don't understand.