Final answer:
To simplify ∘(-9), we recognize that the square root of a negative number requires the imaginary unit 'i', resulting in the simplified form of 3i.
Step-by-step explanation:
The question asks to simplify the square root of a negative number, specifically ∘(-9). In mathematics, the square root of a negative number involves the concept of imaginary numbers. The square root of -1 is defined as the imaginary unit 'i', so ∘(-9) can be simplified to 3i, since ∘(9) is 3 and we then multiply by 'i' to account for the negative under the radical.
The process is straightforward: first acknowledge that ∘(-9) = ∘(9) * ∘(-1). Then, simplify ∘(9) to 3 and replace ∘(-1) with 'i'. Thus, the simplified form in radical expression is 3i.