Bella B.

asked • 10/21/13

Find a bound on the real zeros of the polynomial function.

x4-7x2-18
 
please step by step instructions.
 
Thanks ;-)

2 Answers By Expert Tutors

By:

Nataliya D. answered • 10/21/13

Tutor
New to Wyzant

Patient and effective tutor for your most difficult subject.

Bella B.

not understanding this the answer in the choice was 19 and -19. how did they get that answer?
 
thank you
Report

10/21/13

Nataliya D.

Sorry Bella, missed the word "bound"

"To bound on the real zeros of the polynomial function" means to find an interval where graph of function intercepts the x-axis. 

For this method, the leading coefficient must be "1" (that what we have).

Let's write down all the coefficients: 1, - 7, - 18.

Let's drop the leading coefficient and remove the minus signs: 7, 18. 

BOUND 1 is the largest value plus 1 is (18 + 1) = 19

BOUND 2 is sum of all values, that is (7 + 18) = 25

My apology once again :)
Report

10/21/13

Nataliya D.

.... All roots will be within plus or minus of 19 or 25, but the smallest "bounds" value is the answer.
-19, 19
Report

10/21/13

Bella B.

Thank You so much you are very helpful,
Report

10/21/13

Evan P. answered • 10/21/13

Tutor
4.9 (173)

Knowledgeable and Engaging Tutor

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.

OR

Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.