1: how many entries of A can be chosen independently, if A=A transpose is a 5*5 matrix?


2: how do L and D (still 5*5)give the same number of choices?


3: how many entries can be chosen if A is skew-symmetric?

 

Why do you think these questions are mysterious? Do you have an approach for finding the solution? Tell us what you think.

 

Where did these come from ?

Sounds like a Critical Thinking question from Algebra 2 days, or possibly a Differential Equations question.

I think in light of my finals coming up... i need to do more homework and less puzzles... im trying to put those questions out of my mind.... lol.

Take care.

 

1: how many entries of A can be chosen independently, if A=A transpose is a 5*5 matrix?

Simple: 15 entries.