- #1
JerryKelly
- 11
- 0
Let A be an nxn skew symmetric mx.(A^T=-A).
i) Show that if X is a vector in R^n then (X,AX)=0
ii) Show that 0 is the only possible eigenvalue of A
iii)Show that A^2 is symmetric
iv)Show that every eigenvalue of A^2 is nonpositive.
v)Show that if X is an eigenvector of A^2 , then so is AX
vi)With X as in v), show that the subspace W spanned by X and AX is an A-subspace.
vii)Assuming AX not= 0. let U=X/||X||, V=AX/||AX||. Show that AU=(AU,V)V and that AV=-(AU,V)U.
ix) Show if U,V,U3 , ...,Un is an orthonormal basis of R^n, then the mx of a reletive to this basis has the form (0,b,0,0...0;-b,0,0,0...0;0,0,0,a,0...0;0,0,-a,0,0...0;C some format to the end), where C is skew symmetric (n-2)x(n-2) mx.
Thanks!
i) Show that if X is a vector in R^n then (X,AX)=0
ii) Show that 0 is the only possible eigenvalue of A
iii)Show that A^2 is symmetric
iv)Show that every eigenvalue of A^2 is nonpositive.
v)Show that if X is an eigenvector of A^2 , then so is AX
vi)With X as in v), show that the subspace W spanned by X and AX is an A-subspace.
vii)Assuming AX not= 0. let U=X/||X||, V=AX/||AX||. Show that AU=(AU,V)V and that AV=-(AU,V)U.
ix) Show if U,V,U3 , ...,Un is an orthonormal basis of R^n, then the mx of a reletive to this basis has the form (0,b,0,0...0;-b,0,0,0...0;0,0,0,a,0...0;0,0,-a,0,0...0;C some format to the end), where C is skew symmetric (n-2)x(n-2) mx.
Thanks!