Unformatted text preview: Math 235 Tutorial 8 Problems 1: Classify the following:
a) 1 −5
−5 1 b) Q(x) = 4x2 − 4x1 x2 + 5x2
2 2: For Q(x1 , x2 , x3 ) = 5x2 − 4x1 x2 − 8x1 x3 +8x2 − 4x2 x3 +5x2 , determine the corresponding
symmetric matrix A. By diagonalizing A, express Q(x) in diagonal form and give an
orthogonal matrix that diagonalizes A. Classify Q.
3: Sketch the graph of 2x2 + 4x1 x2 − x2 = 4 showing both the original and new axes.
Find the equation of the asymptotes.
4: Prove that if A is a positive deﬁnite symmetric matrix, then A is invertible.
5: Prove that if B is any invertible n × n matrix, then A = B T B is a positive deﬁnite
symmetric matrix. 1 ...
View Full Document
- Fall '08
- Math, Diagonal matrix, Orthogonal matrix, Symmetric matrix