I have this question:

"A particle initially 4 metres to the right of the origin, has a velocity in metres per second (m/s) given by:

$\displaystyle \[v = - 2\pi \sin \left( {\frac{\pi }{2}t} \right)\]$

Find the expression for the displacement of the particle as a function of the time and hence find when the particle first passes through the origin"

So when i find t do i find it with the calculator on degrees or radians? see in radians it first passes through the origin at 1 second, but in degrees it first passes the origin at 57.29577951