Simple formula, please help

[lesodk]

I have this formula in my book:
$$\[ a = - \omega x^{2} \]$$
Can anyone help me show how to show that this formula is true?

 

[rock.freak667]

What does that formula relate to?

If it is supposed to relate to SHM then the equation is supposed to be $a=- \omega^2 x$

 

[lesodk]

yes sorry, that was what i meant. Do you know how to show the formula from the equations of motion?

 

[alphysicist]

The equation of motion is:

$$m a = - k x$$

What is the definition of $\omega$? Then solve the equation of motion for a.