Question

1. let L:U-V be a linear mapping
2. a) w={x belong u :L(x)=0v} is a subspace ofU
3. 
   
4. b) show if U is finite dimensional ofdimension n , {u1, ...., uk} is a basis for W , and {u1,....,uk,..., un} is a basisi for U , then {L(uk+1) ,...., L(un)} isa basis for L(U) if W no equal to {0u}