Z=[cos(r) -sin(r) 0;sin(r) cos(r) 0;0 0 1];Y=[cos(b) 0 sin(b);0 1 0;-sin(b) 0 cos(b)];X=[1 0 0;0 cos(a) -sin(a);0 sin(a) cos(a)];R=Z*Y*X b1=atan2(-R(3,1),+-sqrt(R(3,2)^2+R(3,3)^2))r1=atan2(R(2,1)/cos(b1),R(1,1)/cos(b1))a1=atan2(R(3,2)/cos(b1),R(3,3)/cos(b1))