Electronics and Communication Engineering (ECE) Exam  >  Electronics and Communication Engineering (ECE) Questions  >  Which one of the following options correctly ... Start Learning for Free
Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?
  • a)
    Four left half plane (LHP) roots
  • b)
    One right half plane (RHP) root, one LHP root and two roots on the imaginary axis
  • c)
    Two RHP roots and two LHP roots
  • d)
    All four roots are on the imaginary axis
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
Which one of the following options correctly describes the locations o...

⇒ 2 sign changes and 1 ROZ
⇒ 2 poles in right half of S-plane
And symmetrical poles in the LHS-plane.
View all questions of this test
Most Upvoted Answer
Which one of the following options correctly describes the locations o...
Explanation:
The given equation is s^4 + s^2 + 1 = 0. To find the locations of the roots of this equation on the complex plane, we can use the fact that the roots of a polynomial with real coefficients come in complex conjugate pairs. Therefore, we can first solve for the roots of the quadratic equation s^2 = (-1 ± √3i)/2 using the quadratic formula.

Solving for the roots of the quadratic equation:
s^2 = (-1 ± √3i)/2
s = ± sqrt[(-1 ± √3i)/2]

We can simplify this expression by rationalizing the denominator:

s = ± sqrt[-(1 ± √3i)]/sqrt(2)
s = ± (1/√2) sqrt(-(1 ± √3i))(√2/2 ± √2/2i)
s = ± (1/√2) (√2/2 ± √6/2i)

Therefore, the roots of the quadratic equation are:

s1 = (1/√2)(√2/2 + √6/2i) = (1/2)(1 + √3i)
s2 = (1/√2)(√2/2 - √6/2i) = (1/2)(1 - √3i)

Finding the locations of the roots on the complex plane:
Now, we can use these roots to find the locations of the roots of the original equation s^4 + s^2 + 1 = 0 on the complex plane. We can do this by factoring the original equation as follows:

s^4 + s^2 + 1 = (s^2 + s√3i + 1)(s^2 - s√3i + 1)

Using the roots of the quadratic equation we found earlier, we can write these factors as:

s^2 + s√3i + 1 = (s - s1)(s - s2)
s^2 - s√3i + 1 = (s + s1)(s + s2)

Therefore, the roots of the original equation are the roots of these two factors, which are:

s1 = (1/2)(1 + √3i) --> RHP root
s2 = (1/2)(1 - √3i) --> RHP root
-s1 = -(1/2)(1 + √3i) --> LHP root
-s2 = -(1/2)(1 - √3i) --> LHP root

Therefore, the locations of the roots of the equation s^4 + s^2 + 1 = 0 on the complex plane are two roots in the right half plane (RHP) and two roots in the left half plane (LHP).
Attention Electronics and Communication Engineering (ECE) Students!
To make sure you are not studying endlessly, EduRev has designed Electronics and Communication Engineering (ECE) study material, with Structured Courses, Videos, & Test Series. Plus get personalized analysis, doubt solving and improvement plans to achieve a great score in Electronics and Communication Engineering (ECE).
Explore Courses for Electronics and Communication Engineering (ECE) exam

Top Courses for Electronics and Communication Engineering (ECE)

Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer?
Question Description
Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? for Electronics and Communication Engineering (ECE) 2024 is part of Electronics and Communication Engineering (ECE) preparation. The Question and answers have been prepared according to the Electronics and Communication Engineering (ECE) exam syllabus. Information about Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? covers all topics & solutions for Electronics and Communication Engineering (ECE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer?.
Solutions for Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Electronics and Communication Engineering (ECE). Download more important topics, notes, lectures and mock test series for Electronics and Communication Engineering (ECE) Exam by signing up for free.
Here you can find the meaning of Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer?, a detailed solution for Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? has been provided alongside types of Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice Which one of the following options correctly describes the locations of the roots of the equation s4 + s2 + 1 = 0 on the complex plane?a)Four left half plane (LHP) rootsb)One right half plane (RHP) root, one LHP root and two roots on the imaginary axisc)Two RHP roots and two LHP rootsd)All four roots are on the imaginary axisCorrect answer is option 'C'. Can you explain this answer? tests, examples and also practice Electronics and Communication Engineering (ECE) tests.
Explore Courses for Electronics and Communication Engineering (ECE) exam

Top Courses for Electronics and Communication Engineering (ECE)

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev