NPTEL Basic Linear Algebra 2020
Assignment 3 - Subjective
Course Instructor: Prof. I. K. Rana Course TA: S. Venkitesh
Deadline: Wednesday, February 19, 2020, 23:59 IST
(1) Consider the following homogeneous system of linear equations.
x + 2y = 0, ax + 8y + 3z = 0, by + 5z = 0.
(a) Find a value of a which will make it necessary during Gaussian elimination to inter-
change rows in the coefficient matrix. [2]
(b) Suppose a does not have the value obtained in part (a). Find the values of b so that
the system has a nontrivial solution. [3]
(c) Suppsose a does not have the value obtained in part (a) and b = 100. Suppose
further that the value of a is chosen so that the solution to the system is not unique.
Find the general solution to the system. [5]
(2) Consider the following system of equations.
x + y + z = 2, x + 3y + 3z = 0, x + 3y + 6z = 3.
(a) Use Gaussian elimination to convert the coefficient matrix to REF. [2]
(b) Solve the system. [3]
(c) Let A denote the coefficient matrix given. The rowspace (columnspace) of A is the
set of all linear combinations of the rows (columns) of A. Find a basis of the rowspace
and the columnspace of A. [5]