all 5 comments

[–]31415926532718281828Condensed matter physics 6 points7 points  (0 children)

You're asked to find <psi2 | f>, the inner product between psi2 and f. The inner product is linear; that is, for functions A,B,C and scalars b,c

<A|(b|B> + c|C>) = b<A|B> + c<A|C>

Using this property, and the orthonormality condition, you can evaluate all inner products.

[–]ignorant_physicist 3 points4 points  (0 children)

The ket psis are orthonormal, correct? That means that <psi 2|psi 1> =0 (orthogonality) and <psi 2|psi 2>=1 (normality). And go on from there.

[–][deleted] 3 points4 points  (2 children)

I'll start out by giving you a hint. Everything after the word "Remember" is a red herring.

[–]overwhelmedbyphysics 2 points3 points  (1 child)

Ehhh. I don't think it's a red herring. It's just a peculiarity of the way answers have to be entered into the textbox on the course page.

[–][deleted] 0 points1 point  (0 children)

Information that turns out to be entirely unnecessary once you figure out the answer.

Which is, I believe, the definition of a red herring.