A Set of Five Possible Wave Functions Is Given Below

Multiple Choice

A set of five possible wave functions is given below, where L is a positive real number.
Ψ₁(x) = Ae^-x, for all x ψ₂(x) = A cos x, for all x
Ψ₃(x) =
Ψ₄(x) =
Ψ₅(x) =
Which of the five possible wave functions are normalizable? (There may be more than one correct choice.)

A) ψ₁(x)
B) ψ₂(x)
C) ψ₃(x)
D) ψ₄(x)
E) ψ₅(x)