# Search results

1. ### Is this solvable

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?
2. ### Is this solvable

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.
3. ### Is this solvable

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.
4. ### Is this solvable

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.
5. ### Where can I learn Quick math - Help

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.