# Why is a QM wave function not normalizable

1. Feb 9, 2007

### Ed Quanta

In quantum mechanics, why is a wave function not normalizable if it always has the same sign as its second derivative?

2. Feb 10, 2007

### Meir Achuz

In 1D, if f"/f is positive, the function curves away from the x axis.
To be normalizable, it must in some region curve toward the x axis.

3. Feb 12, 2007

### dextercioby

Your question doesn't make (too much) sense, since a wave function is a complex (generally with a nonzero imaginary part) valued function and to say that $a+ib >0$ makes no sense.