A community for students.
Here's the question you clicked on:
 0 viewing
pinkdollbaby1234
 2 years ago
i dont understand how to do this
use descartes rule of signs to describe the root of
h(x)=4x^45x^3+2x^2x+5
pinkdollbaby1234
 2 years ago
i dont understand how to do this use descartes rule of signs to describe the root of h(x)=4x^45x^3+2x^2x+5

This Question is Closed

richyw
 2 years ago
Best ResponseYou've already chosen the best response.1\[h(x)=4x^45x^3+2x^2x+5\]how many times does it change signs?

richyw
 2 years ago
Best ResponseYou've already chosen the best response.1i see 4 now do it for \(h(x)\)...

pinkdollbaby1234
 2 years ago
Best ResponseYou've already chosen the best response.0okay so what do you mean by that solve for h?

richyw
 2 years ago
Best ResponseYou've already chosen the best response.1no \[h(x)=4(x)^45(x)^3+2(x)^2(x)+5\]Now simplify that, and then count the sign changes.

pinkdollbaby1234
 2 years ago
Best ResponseYou've already chosen the best response.0oh okay so i would plug in 4 for x since it changes four times or is im wrong again?

richyw
 2 years ago
Best ResponseYou've already chosen the best response.1yeah you are wrong. this is what you should get.\[h(x)=4x^4+5x^3+2x^2+x+5\]Now how many times does the sign change places there?

pinkdollbaby1234
 2 years ago
Best ResponseYou've already chosen the best response.0the sign doesnt change anymore cuz all are equal?

richyw
 2 years ago
Best ResponseYou've already chosen the best response.1yup so you can conclude that there are no negative roots, and either 4, 2 or 0 positive roots. You also know that there are 4 roots total. so you can either have 4 positive real and 0 complex, 2 and 2, or 0 real positive roots and 4 complex roots.

pinkdollbaby1234
 2 years ago
Best ResponseYou've already chosen the best response.0omg thay seem soo simple i have to practice on this more but thankyou so much u help me understand it a bit

richyw
 2 years ago
Best ResponseYou've already chosen the best response.1yup no worries! And in this case that is all it can tell you. Sometimes it can tell you exactly how many of each there are, but sometimes it gives you a few options. It is still useful though because you can use it before you use other methods to get an idea what you are looking for...
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.