1. ## percentage difference?

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!

2. You probably want for percentage difference for a given value. So yes you should give a value and solve.
But in my opinion the formula would rather be $\displaystyle \frac{|sin\theta - \theta|}{sin\theta}$ since you usually approximate $\displaystyle sin\theta$ by $\displaystyle \theta$