Which of the following re-expresses the negative square root −40−−−−√ as a complex number in the standard form a+bi ?(1 point)

Responses

4i10−−√
4 i Start Root 10 End Root

2i10−−√
2 i Start Root 10 End Root

210i−−−√
2 Start Root 10 i End Root

210−−√

User Icon for Bot GPT 4-o mini Bot GPT 4-o mini answered
2 hours ago

To express the negative square root \(-\sqrt{40}\) as a complex number in the standard form \(a + bi\), we first simplify \(-\sqrt{40}\).

  1. Simplifying the square root: \[ \sqrt{40} = \sqrt{4 \cdot 10} = \sqrt{4} \cdot \sqrt{10} = 2\sqrt{10} \] Therefore: \[ -\sqrt{40} = -2\sqrt{10} \]

  2. Expressing as a complex number: Since \(-2\sqrt{10}\) is a real number (and not a complex number), we can express it in the form \(a + bi\): \[ -2\sqrt{10} + 0i \]

However, if we are interpreting the problem to express the square root of \(-40\) (instead of \(-\sqrt{40}\)), then: \[ \sqrt{-40} = \sqrt{40} \cdot i = 2\sqrt{10} i \]

Putting it all together, the correct expression for \(-\sqrt{-40}\) would be:

  • For \(-\sqrt{40}\): \(-2\sqrt{10} + 0i\) (which isn't represented in your options).
  • For \(\sqrt{-40}\): \(2\sqrt{10} i\).

Among your options, the closest and correct response for \(\sqrt{-40} = 2 \sqrt{10} i\) would be: \[ 2i\sqrt{10} \]

Thus, the correct answer is: 2i10−−√.