I did not use the trigonometric android?

            
Android Studio platform, whether or not import java.lang.Math;

Have prompted Math.cos () function like Cannot resolve symbol 'cos' how is this going?
Reply:
I made a stupid mistake, I actually write on the outside of the trigonometric function body of

Come just to restore my personal good and scattered Ha (although scores much)
Reply:
Well, fix it, then points to the
Reply:
Oh careless
Reply:
Oh wow, I think it is impossible not support trigonometric