In: Advanced Math
Question 1
A) Show that the functions y1(t) = 1 + t 2 ; y2(t) = 1 − t 2 are linearly independent directly from the definition of linear independence.
B)Find three functions y1(t), y2(t), y3(t) such that any two of them are linearly independent but three of them are not linearly independent.
a) Suppose that are such that . Then
implies
Second equation gives , and first equation gives
Thus, we have proved that if and only if . Thus, are linearly independent.
b) Let us consider as above, and . We know that are linearly independent by part a).
Proof of the linear independence of :
Suppose that are such that . Then
implies
Solving, we get
Thus, we have proved that if and only if . Thus, are linearly independent.
Proof of the linear independence of :
Suppose that are such that . Then
implies
Solving, we get
Thus, we have proved that if and only if . Thus, are linearly independent.
However, are not linearly independent because