Day 25: Linear Algebra

Today:

• Announcements:
  • Sorry, the exam's not graded yet -- by Friday
  • Octave is back up and running....

• Graded homework 4.1, problems 14 and 30
  • #30: the problem asks us to show that

    (*) cu=0

    where c is non-zero implies that u=0.

    We know this because of axiom 10: 1u=u. Simply multiply through (*) by the constant 1/c, and invoke the axiom.

• Questions about old stuff?

• Current Business:
  • 4.2: Some Important Subspaces
    • section 4.2 highlights (pdf)

  • 4.3: Linearly Independent Sets; Bases
    • section 4.3 highlights (pdf)