Maya trigonometric functions accept angle argument in radians, not degrees. You need to convert it:
CODE
float $angle_deg = 90;
print sin( deg_to_rad( $angle_deg ) );
Though what you're doing could work but you should learn to do this using transformation matrices because it's more generalized and flexible ( but it may seem complicated at first ).
The procedure is: you build 4x4 transformation matrix and then multiply point coordinate vectors with it to obtain transformed point.
It's a way how 3d transformations are really done in most software.
CODE
// calculate sin and cos
float $angle = 35;
float $sina = sin( deg_to_rad( $angle ) );
float $cosa = cos( deg_to_rad( $angle ) );
// construct a 4x4 rotation matrix for rotation around y axis
float $m[16]= { $cosa, 0, $sina, 0, 0, 1, 0, 0, -$sina, 0, $cosa, 0, 0, 0, 0, 1 };
// rotate point;
float $point[3] = { 1, 0, 0 };
float $transformedPoint[] = pointMatrixMult( $point, $m );
print( $transformedPoint );
Note that if you want to transform normal vector instead of point coordinate vector you actually need to represent it with 4 dimensional vector ( called homogeneous coordinate ) in a form:
vn = { x,y,z,0 }
Since maya's pointMatrixMult handles only 3-dimensional input you can't really transform normal vectors with it.
Alternatively you can use pointMatrixMult node with enabled vectorMultiply attribute to transform vectors correctly but in that case you'll need to make some kind of node graph setup.
Or as an excersize you could write vector-matrix multiplication procedure that handles 4 dimensional vectors. There is plenty of info on this around the web or in any book on linear algebra.
See, that's why is good to go to school - they force you to learn that kind of boring stuff such as matrix multiplication. Bad thing is they mostly don't tell you what it is good for.
