SHM
At extremeties,
x = amplitude
v = 0
a = max
at origin,
x = 0
v = max
a = 0
For the form a = -n^2 x, let a = d/dx(v^2/2)
integrate for v, and use any information they give and the table above to find C
if a particle moves about a point p other than the origin, replace x by...