Description
Problem 4.1: What matrix E puts A into triangular form EA = U? Multiply by E−1 = L to factor A into LU.
⎡ ⎤ 1 3 0
A = ⎣ 2 4 0 ⎦
2 0 1
Problem 4.2: (2.6 #13. Introduction to Linear Algebra: Strang) Compute L
and U for the symmetric matrix
⎡ ⎤
A = ⎢
⎢
⎣
a a a a
a b b b
a b c c
a b c d
⎥
⎥
⎦ .
Find four conditions on a, b, c, d to get A = LU with four pivots.
1
18.06SC Linear Algebra