코드는 아래와 같고 article 서식입니다.

\paragraph{2.}

\subparagraph{a)}

\begin{align*}

\braket{\psi_1 | (\hat{A}+i\hat{B}) \psi_2} 

&= \braket{\psi_1 | \hat{A} \psi_2} + i\braket{\psi_1 | \hat{B} \psi_2}\\

&= \braket{\hat{A} \psi_1 | \psi_2} + i\braket{\hat{B} \psi_1 | \psi_2}\\

&= \braket{\hat{A} \psi_1 | \psi_2} - \braket{i\hat{B} \psi_1 | \psi_2}\\

&= \braket{(\hat{A}-i\hat{B}) \psi_1 | \psi_2}

\end{align*}