Got Homework?
Connect with other students for help. It's a free community.
Here's the question you clicked on:
 0 viewing
pinkdollbaby1234
Group Title
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
 2 years ago
 2 years ago
pinkdollbaby1234 Group Title
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
 2 years ago
 2 years ago

This Question is Closed

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

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

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

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

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

richyw Group TitleBest ResponseYou've already chosen the best response.1
yeah 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?
 2 years ago

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

richyw Group TitleBest ResponseYou've already chosen the best response.1
yup 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.
 2 years ago

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

richyw Group TitleBest ResponseYou've already chosen the best response.1
yup 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...
 2 years ago
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
 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.