If all you want to do is to show that v1 and -v2 are orthogonal, try this: (%i1) sol2:[[1,-(sqrt(4*t^2+q^2-2*p*q+p^2)-q+p)/(2*t),0], [-1,-(sqrt(4*t^2+q^2-2*p*q+p^2)+q-p)/(2*t),0]]; (%o1) [[1,(-sqrt(4*t^2+q^2-2*p*q+p^2)+q-p)/(2*t),0],[-1,(-sqrt(4*t^2+q^2-2*p*q+p^2)-q+p)/(2*t),0]] (%i2) expand(sol2[1] . -sol2[2]); (%o2) 0 BW