Quadratic Forms Question - HELP !!!!!!!!!!!!!


hi guys !

I am trying to learn quadratic forms....afraid I'm no good at it since
I can't seem to solve too many questions.


We have a square matrix A that can be written in the form, A=S + K,
where

S= 1/2.( A + A^T) and K= 1/2.( A - A^T)

S is symmetric while K is a skew-symmetric matrix.

SHOW THAT if X is a column n-tuple, then X^(T) AX= X^(T) SX

Can someone help me please?

Daniella

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