$\displaystyle x=Acos(\omega t+\theta _0)$

$\displaystyle v=-\omega Asin(\omega t+\theta _0)$

$\displaystyle a=-\omega ^2Acos(\omega t+\theta _0)=-(\frac{k}{m})Acos(\omega t+\theta_0)$

$\displaystyle v=\omega Asin(\omega t+\theta _0)$

$\displaystyle (\frac{2\pi t}{T}+\phi _0)$