What is the value of the sin?

If you mean the sine function, it is dependent on an angle. For example, the sine of an angle of zero degrees is zero; the sine of an angle of 90 degrees is one; for an angle of 180 degrees, the sine is again 0; if you make a graph, you get a curve that looks like a wave. In general, the values the sine function can take are between 1 and -1, inclusive.