
Arturo O. answered 07/27/18
Tutor
5.0
(66)
Experienced Physics Teacher for Physics Tutoring
Here is a counterexample to show it is false.
X1 = (1, 0, 0)
X2 = (0, 1, 0)
X3 = (0, 2, 0)
X1 and X2 are linearly independent.
X1 and X3 are linearly independent.
But X2 is not linearly independent of X3, so {X1,X2,X3} is not a linearly independent set.