Express in terms of \( i \). \( \sqrt{-16} \) \( \sqrt{-16}=4 \) (Simplify your answer. Type your answer in the form \( \mathrm{a}+\mathrm{bi} \).)

To express \( \sqrt{-16} \) in terms of the imaginary unit \( i \), follow these steps: 1. **Recall the Definition of \( i \):** \[ i = \sqrt{-1} \] 2. **Express \( \sqrt{-16} \) Using \( i \):** \[ \sqrt{-16} = \sqrt{16 \times (-1)} = \sqrt{16} \times \sqrt{-1} = 4i \] 3. **Write in the Form \( a + bi \):** \[ \sqrt{-16} = 0 + 4i \] However, it's common and perfectly acceptable to write this simply as: \[ \sqrt{-16} = 4i \] **Final Answer:** \[ \sqrt{-16} = 4i \]