Linear Algebra
Tutorial 1
Exercise 1
Exercise 2
Exercise 3
1
Exercise 4
2
Exercise 5
Exercise 6
Solve by Cramer’s rule, if it is possible, these systems of linear equations:
2𝑥 + 4𝑦 + 3𝑧 = 1
a. {3𝑥 − 6𝑦 − 2𝑧 = −2
−5𝑥 + 8𝑦 + 2𝑧 = 4
𝑥−𝑦 =0
𝒃. { −𝑥 +𝑦+𝑧 = 1
𝑥 + 2𝑦 − 3𝑧 = 0
𝑥+𝑦+𝑧 =1
𝒄. {−𝑥 + 𝑦 − 𝑧 = 2
𝑥−𝑦+𝑧 =1
Exercise 7
3
Exercise 8
Let A be the following matrix
1 3
𝐴=[ ]
−2 −8
1) Find 𝐴2 ; 𝐴−1 or show that A is not invertible.
2) Find the values of p and q such that 𝐴2 = 𝑝𝐴 + 𝑞𝐼 where 𝐼 is 2×2 identity matrix.
3) Let 𝐵 = 𝐴 − 𝑡𝐼 where t is a scalar . For which values of t is B singular.
0
4) Find the solutions to 𝐴2 𝑥 = 𝑏 where 𝑏 = [ ]
1
Exercise 9
1 2 1 7 −6 1
Let 𝐴 = (2 3 2) and 𝐵 = (−4 2 0)
3 4 5 −1 2 −1
1) Find the determinant of matrix A using two methods. Is A regular?
2) Compute 𝐴𝐵 + 2𝐼 where 𝐼 is a 3 × 3 identity matrix. Is the obtained matrix an orthogonal
matrix?
1
3) Using the previous question deduce that 𝐴−1 = − 2 𝐵
𝑥 + 2𝑦 + 𝑧 = −2
4) Let the system of linear equations : {2𝑥 + 3𝑦 + 2𝑧 = 4
3𝑥 + 4𝑦 + 5𝑧 = 8
a) Write the matrix representation for the system.
b) Solve the system using the inverse matrix method.