Calculus help please?

You have your calculator set to read angles as degrees.
Set it to radians.

　
sin(2π/2) = sin(π) = 0
In degrees: sin(180°) = 0

Make sure to set your calculator to radians.

Yours is obviously set to degrees, since
sin(π°) = 0.0548, but π is a radian measure
(always assume radians unless otherwise stated)

Should be 0.

sin(2pi / 2) = sin(pi) = 0.

Check the measurement...you might be measuring in degrees instead of radians. Anything with pi is a clear indication of radian measure.

sin((π·2)/2) = sin(π) = 0

sin(2π/2)=sin(π)=0