Let T W Rn ! Rm be a linear transformation. Show that if T maps two linearly independent vectors onto a linearly dependent set, then the equation T .x/ D 0 has a nontrivial solution. [Hint: Suppose u and v in Rn are linearly inde- pendent and yet T .u/ and T .v/ are linearly dependent. Then 495 c1T .u/ C c2T .v/ D 0 for some weights c1 and c2, not both zero. Use this equation.]

Respuesta :

Answer:

The solution proves that the equation has a non-trivial solution.  

Step-by-step explanation:

We want to show that the equation has nontrivial solutions for which [tex]c_{1} T(v_{1} ) + c_{2} T(v_{2} ) + c_{3} T(v_{3}) = 0[/tex]

Let [tex]c_{i}[/tex] be a set of non-zero numbers such that that [tex]c_{1} v_{1} + c_{2} v_{2} + c_{3} v_{3} = 0[/tex]

Because T is a linear solution:

[tex]c_{1}T(v_{1} ) + c_{2} T (v_{2} ) + c_{3} T (v_{3} ) = T (c_{1} v_{1} ) + T(c_{2}v_{2} ) + T(c_{3} v_{3} )[/tex]

                                            = [tex]T(c_{1}v_{1} + c_{2} v_{2} + c_{3} v_{3} )[/tex]

                                            = [tex]T(0)[/tex]

                                            = [tex]T (00)[/tex]

                                            = [tex]0T(0)[/tex]

                                            = 0

This shows that [tex]T( v_{1} )[/tex] are linearly independent with the mapping resulting in a non-trivial solution.