A community for students.
Here's the question you clicked on:
 0 viewing
nubeer
 3 years ago
find all roots of z^5+2z^3+6z^2+12 =0 using demoivre theroem
anyone plz?
nubeer
 3 years ago
find all roots of z^5+2z^3+6z^2+12 =0 using demoivre theroem anyone plz?

This Question is Closed

lgbasallote
 3 years ago
Best ResponseYou've already chosen the best response.0the demoivre theorem i am familiar with is the one in Calculus. Is that the one you're pertaining to?

vishal_kothari
 3 years ago
Best ResponseYou've already chosen the best response.10http://maths.ucd.ie/courses/math1200/algebra/algebranotes83.pdf

mathmate
 3 years ago
Best ResponseYou've already chosen the best response.0You'll see why when you factor the lefthand side of the equation to (z^2+2)*(z^3+6) = 0

nubeer
 3 years ago
Best ResponseYou've already chosen the best response.0ahh yes i think this is the factor this helps alot.. can u tell me how u got that... dont tell me its again hit and trial

Mr.Math
 3 years ago
Best ResponseYou've already chosen the best response.1\[(z^5+2z^3)+(6z^2+12)=z^3(z^2+2)+6(z^2+2)=(z^3+6)(z^2+2).\]

nubeer
 3 years ago
Best ResponseYou've already chosen the best response.0well thanks .. this way is also a good one.. can u tell me any website whichhave questions like these with solutions.

Mr.Math
 3 years ago
Best ResponseYou've already chosen the best response.1This was just a simple factorization, You can search factorization techniques. You still need to solve \((z^3+6)(z^2+2)=0\), which implies \(z^2+2=0\) or \(z^3+6=0\).

Mr.Math
 3 years ago
Best ResponseYou've already chosen the best response.1\(z^2+2=0\) is very easy to solve and you it gives the roots \(z=\pm \sqrt{2}i\).

Mr.Math
 3 years ago
Best ResponseYou've already chosen the best response.1You can use the demoivre theorem to solve \(z^3+6\), (i.e find the third roots of \(6\)).

nubeer
 3 years ago
Best ResponseYou've already chosen the best response.0so this last term will give us three roots?

Mr.Math
 3 years ago
Best ResponseYou've already chosen the best response.1Yep, The notes vishal kothari gave are very good. You should probably read them.

nubeer
 3 years ago
Best ResponseYou've already chosen the best response.0ya i read them all.. they are helpful.. but still was kinda confused of how getting these roots.. but thank you.. do u know any website for more questions about this? with solutions?

Mr.Math
 3 years ago
Best ResponseYou've already chosen the best response.1I don't, but you can search the internet for solutions of polynomials over complex numbers. I would look for you, but I have to leave now.

arijit.mech
 3 years ago
Best ResponseYou've already chosen the best response.0put z=e^ix =cosx+isinx then proceed

nubeer
 3 years ago
Best ResponseYou've already chosen the best response.0@Mr.Math . thank you very much have a nice day :)
Ask your own question
Sign UpFind more explanations on OpenStudy
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
 Engagement 19 Mad Hatter
 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.