Students work in small groups to use completeness relations to change the basis of quantum states.
Imagine a spin-1/2 system prepared in the state:
\[\left|{\psi}\right\rangle = \sqrt{\frac{2}{5}} \left|{+}\right\rangle + i\sqrt{\frac{3}{5}} \left|{-}\right\rangle \]
Use a completeness relation to write this state in the \(S_x\) basis.