Q:

Removing $\cos \theta$ from the given equation?

I have been stuck on a particular question. The question relates to the area of a triangle being equal to the area of a sector. As such, I came to the conclusion that $\sin\frac{\theta}{2} * \cos\frac{\theta}{2} = \frac{1}{2}*\theta $ . But I do not quite understand what to do next! Is there some concept to apply here, or did I simply mess up?
($\theta$ is in radians)

A:

Use the identity:$$\sin\big(\frac{\theta}{2}\big)\cos\big(\frac{\theta}{2}\big)=\frac{1}{2}\sin(\theta)$$ to remove the cosine. Then set $$\frac{1}{2}\sin(\theta)=\frac{1}{2}\theta$$. Now it is much simpler. Can you finish?

