Question: CrossProduct Error

Hello! How i can write this expression in maple?

ma × (Ω' × a )
where is
Omega := Vector(3, [Omega1, Omega2, Omega3])
dT := proc (f) options operator, arrow; add((diff(f, var[k]))*dz[k], k = 1 .. N) end proc
a := Vector(3, {(1) = Ri*n1, (2) = n2*Ri, (3) = n3*Ri-R0})
Please Wait...