yes

Yes

yes

like last time please

start with Sheet 11

sheet 11, please

sheet 11 :)

Sheet 11

I would like to start with sheet 11

yes

no...

thanks!

So if Q(x) is equal to Zero is it Semi-positive-definite or Semi-negative-definite? Because 0 is included in both definitions...

ah okay, thanks!

yes

i think so

yes

So if Q sends all vectors in R^n to 0, q is both negative and positive semidefinite?

Ok great

false

false?

can also be semi-

It could also be semi

no..

yes

thanks!

Isnt a x^2 term missing?

ahaa yes now it's clear

thanks for the example

does this work for all symmetric matrices?

yes

yes

in the opposite, if i know the Eigenvalues, i can directly say the quadratic form is pos/neg/… definite? (even if i dont know the quadr. form yet)

okay thanks

can we use eigenvalues or determinants to see whether a matrix is semi positive or negative

ok thank you

A question to the matrix S, if one of the eigenspaces has a dimension>1, do we always simply use the basis of the eigenspace rather than the eigenvector?

can we use any eigenvectors in the space?

in S

ok thanks

Thanks very much as always :)

thanks!

Thank you

merci

thank you very much

thanks a lot!

Thanks!

you explain so good! thank you

how many sheets are left? 2 or 3?

thanks for your help!

thank you!!

thx