# New to the forums, trouble with an integral

1. Feb 3, 2008

### jhayes25

Hello all, I am new to these forums. I'm having trouble with a problem on homework. It seems simple but it is giving me problems.

It is an indefinite integral: Integral of (Sin(2x))/(Sinx)dx

Is there a way to use substitution? Help is appreciated.

2. Feb 3, 2008

### rocomath

$$\int\frac{\sin{2x}}{\sin x}dx$$

Use the trig identity.

$$\sin{2x}=2\sin x \cos x$$

3. Feb 3, 2008

### awvvu

Use the identity:

$$sin(2x) = 2sin(x)cos(x)$$

4. Feb 3, 2008

### jhayes25

roco, that is correct. Obviously a newb, I have no idea how you did that. I'm sure there are stickies somewhere that I need to read.

5. Feb 3, 2008

### rocomath

Introducing LaTeX Math Typesetting - https://www.physicsforums.com/showthread.php?t=8997

Enjoy!

6. Feb 3, 2008

### jhayes25

Alright, wow that is simple when you now the identities. Guess i should get to learning those lol thx awvvu