Unless Im missing something I thought the half angle formula was
\tan \frac{\theta}{2} = \frac{\sqrt {1-\cos \theta}}{\sqrt{ 1 + \cos \theta}}
Thats not the same as \tan \frac{\theta}{2} = \frac{\sin \theta}{1 + \cos \theta} right? Or am I making a mistake?
Almost, but not quite. It looks pretty tough to put it in that particular form. The way I mentioned works so I guess Ill just stick with that, especially since remembering all those identities is a pain.
Thanks for the suggestions though.
I think I found it. It came to me when I went to get the mail. :)
basically I have this
tan(30)=\frac {\sqrt {1 - \cos^{2} \theta}}{1+\cos(\theta)}
From here I just put it in a quadratic form and solved.
tan(30)=(sin(theta))/(1+cos(theta))
The only way I can solve this is by using the graph on the calculator. There must be a way to solve it by hand though but I cant find it. Maybe Im just not thinking straight but its really getting to me.
I know there are a few tricks to doing things like that in your head but I have forgotten them. The best way though would just be to practice. Start small and just slowly build up to larger numbers.