Prove that if dimV=1\dim V = 1 and TL(V,V)T \in \mathcal L(V,V) then there exists λF\lambda \in F such that T(v)=λvT(v) = \lambda v for all vVv \in V.


Let vv be a basis for VV, and let λ\lambda be such that Tv=λvTv = \lambda v. Since any wVw \in V can be written as w=cvw = cv for cFc \in \mathbf F we have

Tw=cTv=cλv=λw.Tw = cTv = c\lambda v = \lambda w.