I need help on these questions...i really dont get them:

solve:

cosx (cosx-1)=0

and these next two are on the inerval of [0, 2pi)

2sin^2x = 2+cosx

secx + tanx=1

and theres one on harmonic motion i dont get:

the position of the weight relative to the point of equilibrium is given by:

y= 1/12 (cos8t-3sin8t)

find the times when the weight is at the point of equilibrium (y=0) for 0 is less than/ equal to t that is less than/equal to 1.

Thanks!