1. Radians or Degrees for this question?

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

2. Usually questions like these are in radians, unless specified otherwise.

3. The trig functions, as functions, rather than in a triangle, are always in radians.

(Strictly speaking they are defined, for all x, such that x is NOT an angle at all and so not in either "radians" or "degrees" but the definitions are such as to fit the "right triangle" definitions when x is in radians.)

4. Wow thanks heaps Hallsofivy that description helps so much. Before you said that i had no idea it worked that way, but now that i think about it, that would make sense. Thanks also Educated