# #

The displacement of a mass from its equilibrium position as it oscillates on a horizontal spring satisfies the equation $$x(t)= Acos(\omega t + \phi_0)$$.

At $$t = 0 s$$, if $$x = - \frac{A}{2}$$, what are the two possible values of $$\phi_0$$ between 0 and 2$$\pi$$ radians?

## Part 1#

Enter the higher value here.

Please enter a numeric value.

## Part 2#

Enter the lower value here.