Let two functions and be defined for 0 x . Explain why (x) = x cannot be a wave function but

Let two functions ψ and Φ be defined for 0 ≤ x ≤ ∞. Explain why ψ(x) = x cannot be a wave function but Φ(x) = e −kx (with k being a positive finite number) could be a valid wave function.