In Problems 17,
18_(,)19_()
, and
20_()
the given vectors are solutions of a system
x^(')=Ax
. Determine whether the vectors form a fundamental set on the interval
(-\infty ,\infty )
. 17.
x_(1)=((1)/(1))e^(-2t),x_(2)=((1)/(-1))e^(-6t)