Time Period:
$$ T= 2 \pi \sqrt{\frac{m}{k}} $$Frequency:
$$ f= \frac{1}{2\pi} \sqrt{\frac{k}{m}} $$Instantaneous displacement:
$$ v= v_{0} \sqrt{(1- \frac{x^2}{x^2_{0}})}$$Potential Energy:
$$ P.E= \frac{1}{2}kx^2 $$Kinetic Energy:
$$ K.E= \frac{1}{2}k(x^2_{0}-x^2) $$