Proving a trigonometric identity with sin and cos

[Feodalherren]

Homework Statement

Homework Equations

Any trig formulas

The Attempt at a Solution

The yellow paper is me switching everything to sin and cos to see if that helps but it doesn't. I'm completely stuck here.

 

[Feodalherren]

Oh yeah, it's problem fifty. Forgot to say that :).

 

[SammyS]

Oh yeah, it's problem fifty. Forgot to say that :).

What yellow paper ?

 

[Feodalherren]

You can't see the images?

 

[SammyS]

You can't see the images?

Not at all.

 

[Feodalherren]

http://img839.imageshack.us/img839/2928/one0001.jpg

Does that work?

 

[jedishrfu]

at the step where you combine the two fractions you sucked in the minus sign and then lost a minus as you multiplied the second term with 1-tan(theta). Do you see that?

you should instead have: 4 tan(theta) / ( 1 - tan^2(theta) )

 

[Feodalherren]

Got it. Thank you!