This is for my physics class, but it's a math related problem.

What is the percentage difference between $\displaystyle \alpha$ and sin($\displaystyle \alpha$)?

Teacher said to use:

$\displaystyle \frac{\alpha - sin(\alpha)}{\alpha}$

then multiply by 100 to get the percentage. But I guess i just don't understand what i'm exactly supposed to do. Give $\displaystyle \alpha$ a value and solve? Any help is greatly appreciated!