in reply to Rotate a 3D vector

Back to the trenches with me. I'm starting with a 2d space till i can wrap my head around it. The code and examples i am finding are not matching up in 3d space. Here's my closest attempt which still is wrong. Can anyone help?
# 2 points on a plane my $x = 2; my $y = 1; #yang is the y-angle 0-360 i want to rotate by my $yang = 45; #convert yang to radians $yang = 3.14159265358979*$yang/180; #rad is the radius of my sphere my $rad = sqrt($x**2 + $y**2); my $x = cos($yang)*$rad; my $y = sin($yang)*$rad; print "x=$x\ny=$y\n";
Advice appreciated.