Final answer:
To construct a 4 x 3 matrix with a linearly independent set and not in the span of [a, a^2], you can set up a matrix with the given conditions.
Step-by-step explanation:
In order to construct a 4 x 3 matrix where {a, a^2, a^3, 1} is a linearly independent set and not in the span of [a, a^2], we can set up the following matrix:
aa^2a^31100001000010
This matrix satisfies the given conditions because the first row represents the elements {a, a^2, a^3, 1}, which is a linearly independent set, and the second and third row represent the elements [a, a^2], which is not in the span of [a, a^2].