Originally Posted by

**masters** Hello again skeske1234,

Have we been helpful, yet.

To your first question, you may cancel across factors like this:

$\displaystyle \frac{2 \sin x \cos x}{\sin x}=\frac{2}{1}\cdot \frac{{\rlap{////}\sin x}}{{\rlap{////}\sin x}} \cdot \frac{\cos x}{1}=2 \cos x$

As far as $\displaystyle \frac{\cos 2x}{\cos x}$ goes, consider:

$\displaystyle \frac{\cos(2 \cdot 30)}{\cos(30)}$

If you tried to cancel out the 30, what do you have? $\displaystyle \cos 2$?? Does that make sense?