1
A third degree polynomial could have one or three real roots.
Actually, the roots of a Hurwitz polynomial are in the left half of the complex plain, not on the imaginary axis. As for the reason, that is because the polynomial is DEFINED to be one that has that kind of roots.
The given polynomial does not have factors with rational coefficients.
For a general polynominal, the cubic, quartic, and greater formulæ are too hellishly hard to work with, so you would need to plot the function or use Newton's/somesuch method to count the real roots by hand. If the polynomial has integral roots, you can use synthetic division to peel off the degrees to see if they factor wholely into binominals; then all roots will be real and explicit. Good luck:
The similarities are that they are polynomial functions and therefore continuous and differentiable.A real cubic will has an odd number of roots (and so must have a solution), a quartic has an even number of roots and so may have no solutions.
Descartes' rule of signs (see related link) can help you determine the maximum number of real roots. If the polynomial is odd powered, then there will be at least one real root. Any even powered polynomial can be factored into a bunch of quadratics [though they may not be rational or even pretty], and any odd-powered polynomial can be factored into a bunch of quadratics and one linear (this one would have the real root). So the quadratics may have pairs of real or complex roots (having an imaginary component).To clarify, when I say complex, I'm referring to the fact that there will be an imaginary component to the root, because actually the real numbers is a subset of the set of complex numbers.The order of the polynomial will tell you how many roots it will have. If you can graph the polynomial, then you can see if it crosses the x axis. If it is a 5th order polynomial, and crosses the x axis 3 times, then there are 3 real roots (the other two roots are complex).
In answering this question it is important that the roots are counted along with their multiplicity. Thus a double root is counted as two roots, and so on. The degree of a polynomial is exactly the same as the number of roots that it has in the complex field. If the polynomial has real coefficients, then a polynomial with an odd degree has an odd number of roots up to the degree, while a polynomial of even degree has an even number of roots up to the degree. The difference between the degree and the number of roots is the number of complex roots which come as complex conjugate pairs.
A polynomial of degree ( n ) can have at most ( n ) unique roots. This is due to the Fundamental Theorem of Algebra, which states that a polynomial of degree ( n ) has exactly ( n ) roots in the complex number system, counting multiplicities. Therefore, if all the roots are distinct, the maximum number of unique roots is equal to the degree of the polynomial.
A fourth degree polynomial function can have up to four unique roots. However, the actual number of unique roots can be fewer, depending on the polynomial's coefficients and the nature of its roots. Roots can be real or complex, and some roots may be repeated (multiplicity). Thus, the number of unique roots can range from zero to four.
The "roots" of a polynomial are the solutions of the equation polynomial = 0. That is, any value which you can replace for "x", to make the polynomial equal to zero.
A polynomial of degree ( n ) can have at most ( n ) real zeros. This is a consequence of the Fundamental Theorem of Algebra, which states that a polynomial of degree ( n ) has exactly ( n ) roots in the complex number system, counting multiplicities. Therefore, while all roots can be real, the maximum number of distinct real zeros a polynomial can possess is ( n ).
Sort of... but not entirely. Assuming the polynomial's coefficients are real, the polynomial either has as many real roots as its degree, or an even number less. Thus, a polynomial of degree 4 can have 4, 2, or 0 real roots; while a polynomial of degree 5 has either 5, 3, or 1 real roots. So, polynomial of odd degree (with real coefficients) will always have at least one real root. For a polynomial of even degree, this is not guaranteed. (In case you are interested about the reason for the rule stated above: this is related to the fact that any complex roots in such a polynomial occur in conjugate pairs; for example: if 5 + 2i is a root, then 5 - 2i is also a root.)
A fifth-degree polynomial function will have exactly five roots, counting multiplicities. This means that some of the roots may be repeated or complex, but the total number of roots, including these repetitions, will always equal five. If the polynomial has real coefficients, some of the roots may also be non-real complex numbers, which occur in conjugate pairs.
A root of a polynomial is a value of the variable for which the polynomial evaluates to zero. In other words, if ( p(x) ) is a polynomial, then a number ( r ) is a root if ( p(r) = 0 ). Roots can be real or complex and are critical for understanding the behavior and graph of the polynomial function. The Fundamental Theorem of Algebra states that a polynomial of degree ( n ) has exactly ( n ) roots, counting multiplicities.
Variation of sign is a mathematical concept used primarily in the context of polynomial functions to determine the number of positive and negative roots. It is based on Descartes' Rule of Signs, which states that the number of positive roots of a polynomial is equal to the number of sign changes between consecutive non-zero coefficients, or less than that by an even integer. Similarly, the number of negative roots can be found by applying the rule to the polynomial evaluated at negative values. This method provides a way to estimate the nature and number of roots without finding them explicitly.
In the complex field, a polynomial of degree n (the highest power of the variable) has n roots. Some of these roots may be multiple roots. However, if the domain is the real numbers (or a subset) then there is no easy way. The degree only gives the maximum number of roots - there may be no real root. For example x2 + 1 = 0.
A third degree polynomial could have one or three real roots.