16.-Linear-Algebra-by-Kenneth-Hoffman · Problem 3.2.10
Linear Transformations
Mathematics — Linear Algebra · onto-nonsingular-rectangular
Problem
Let A be an m×n matrix with entries in F and let T be the linear transformation from Fn×1 into Fm×1 defined by T(X)=AX. Show that if m<n it may happen that T is onto without being non-singular. Similarly, show that if m>n we may have T non-singular but not onto.