Quantcast

Got Homework?

Connect with other students for help. It's a free community.

  • across
    MIT Grad Student
    Online now
  • laura*
    Helped 1,000 students
    Online now
  • Hero
    College Math Guru
    Online now

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

dellzasaur

Can someone please check my work?? Wanna make sure I'm doing this right! Simply each number by using the imaginary number i. thanks!

  • one year ago
  • one year ago

  • This Question is Closed
  1. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\sqrt{-7}\] = 7i or \[i \sqrt{7}\]

    • one year ago
  2. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\sqrt{-81}\] = 3i

    • one year ago
  3. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\sqrt{-16}\] = \[2i \sqrt{4}\]

    • one year ago
  4. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    \[3\sqrt{-9}\] = \[3i\]

    • one year ago
  5. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    The last one is wrong.

    • one year ago
  6. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @dido525 Oh wow!! Thank you. I can't believe I'm doing these somewhat right lol. Would it be \[3i \sqrt{3}\] ?? And there was also a problem that was \[\sqrt{-72}\] I got: \[2i \sqrt{3}\]

    • one year ago
  7. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    The last one should be 9i.

    • one year ago
  8. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    Well think about it WITHOUT the negative.

    • one year ago
  9. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1352593737003:dw|

    • one year ago
  10. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1352593754329:dw|

    • one year ago
  11. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    Now what would you do?

    • one year ago
  12. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    is that a 4 and 18? I would think to factor them to 2 x 2 and 9 x 2 maybe

    • one year ago
  13. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    but inside of the radicals

    • one year ago
  14. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    |dw:1352593862710:dw|

    • one year ago
  15. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @Dido525

    • one year ago
  16. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    No No.

    • one year ago
  17. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    |dw:1352594047004:dw|

    • one year ago
  18. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @Dido525 Oh ok! That made since. I was using 8, 9, and i to make -72

    • one year ago
  19. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay :) .

    • one year ago
  20. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @Dido525 Thank you so much for all your help :) Makes me feel more confident about simplying them!

    • one year ago
  21. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    *simplifying whoops

    • one year ago
  22. Zarkon
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\sqrt{-72}=\sqrt{(-1)\cdot2\cdot 36}\] \[=6i\sqrt{2}\]

    • one year ago
  23. Dido525
    Best Response
    You've already chosen the best response.
    Medals 0

    Okay that works too.

    • one year ago
  24. chaguanas
    Best Response
    You've already chosen the best response.
    Medals 0

    Getting the i right, but need to look at \[\sqrt{81} and \sqrt{16}\]

    • one year ago
  25. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @chaguanas Would I do \[3i \sqrt{3}\] for -81? and 4i or \[4i \sqrt{4}\] for -16?

    • one year ago
  26. Zarkon
    Best Response
    You've already chosen the best response.
    Medals 1

    do you know what \(\sqrt{81}\)is?

    • one year ago
  27. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @Zarkon 9

    • one year ago
  28. Zarkon
    Best Response
    You've already chosen the best response.
    Medals 1

    well...\[\sqrt{-81}=\sqrt{(-1)81}=i9=9i\]

    • one year ago
  29. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @Zarkon Ohh so that's how you do it. You wouldn't factor the 9 out to a 3?

    • one year ago
  30. Zarkon
    Best Response
    You've already chosen the best response.
    Medals 1

    no

    • one year ago
  31. Zarkon
    Best Response
    You've already chosen the best response.
    Medals 1

    for any \(a>0\) \[\sqrt{-a^2}=a\cdot i\] so \[\sqrt{-81}=\sqrt{-9^2}=9i\]

    • one year ago
  32. Zarkon
    Best Response
    You've already chosen the best response.
    Medals 1

    \[\sqrt{-16}=\sqrt{-4^2}=4i\]

    • one year ago
  33. dellzasaur
    Best Response
    You've already chosen the best response.
    Medals 1

    @Zarkon Oh alright! I'm not sure if my teacher taught me about the a>0 thing but that makes sense. Thank you very much :) Explained a lot.

    • one year ago
    • Attachments:

See more questions >>>

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.