Respuesta :

Answer: Fourth option CD=DC=I 

Answer:

4) CD =DC = 1  is true .

Step-by-step explanation:

Given  : If C and D are matrices and C is the inverse of D.

To find  :  which of the following is true.

Solution : We have given that  C and D are matrices and C is the inverse of D.

By the inverse matrix rule  : [tex]A^{}A^{-1}  = [tex]A^{-1} A^{}[/tex]= 1[/tex].

Where [tex]A^{-1}[/tex] is inverse of A matrix .

Then CD =DC = 1

Therefore, 4) CD =DC = 1  is true .