Question

WHat is a quick mathod of determine wheter a quadratic form is positive definite, postive semidefinite etc

Answer 1

Google pretty much just give a general theory, there is no way to quickly calculate, I know the definitions of them already

Answer 2

My girlfriend has a homework question saying that determine the quartic form x^t*A*x where A is the matix( 2,3 is p.d. or p.sd, or n.d or n.sd or indefinite
3, 8)

Answer 3

so the Q form comes out as 2x1^2+6x1x2+8x2^2

Answer 4

nvm, I got it