According to the Fundamental Theorem of Algebra, every
nonconstant polynomial f (x) ∈
C[x] with complex coefficients has a complex root.
(a) Prove every nonconstant polynomial with complex coefficients
is a product of linear polynomials.
(b) Use the result of the previous exercise to prove every
nonconstant polynomial with real coefficients is a product of
linear and quadratic polynomials with real coefficients.
Prove by induction that it follows from Fundamental Theorem of Algebra that every f(x) ∈ C[x] can be written into a product of linear polynomials in C[x].
(a) Are there matrices A,B∈Mn(R)A,B∈Mn(R) such that AB−BA=IAB−BA=I. (b) Suppose that A,B∈Mn(R)A,B∈Mn(R) such that (AB−BA)2=AB−BA(AB−BA)2=AB−BA. Show that AA and BB are commutable.
Let A ∈ Mn(R) such that I + A is invertible. Suppose that B = (I − A)(I + A)-1(a) Show that B = (I + A)−1(I − A)(b) Show that I + B is invertible and express A in terms of B.