Complex number polynomial, with no root given

In summary, the given polynomial has a real root and in order to find all solutions, one can assume a real solution and see if it satisfies the equation. By doing so, it was determined that the real and imaginary parts of the assumed solution must both equal zero, resulting in a final answer of two solutions.
  • #1
Jarfi
384
12

Homework Statement



z^3 + (-5+2i)z^2 + (11-5i)z -10+2i =0 has a real root, find all the solutions to this equation.


The Attempt at a Solution



I have only solved imaginary number polynomials with a given root, but this has no given root, how do I find the real solution? that I can then use to factor it and find the rest of the solutions.
 
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  • #2
If you have no other techniques available, you can always assume a real solution and see if it satisfies the equation.
 
  • #3
SteamKing said:
If you have no other techniques available, you can always assume a real solution and see if it satisfies the equation.

Oh nevermind, I found out how you do it, you just define a as a real number, put it in and get a real and imaginary part, both real and imaginary part are suppost to be equal to zero, so their mutual solution is the available real solution, this gave me the answer of two.
 
  • #4
SteamKing said:
If you have no other techniques available, you can always assume a real solution and see if it satisfies the equation.

I already knew the 2 was an answer but my teacher would frown upon me if I'd assume a solution.
 

Related to Complex number polynomial, with no root given

1. What is a complex number polynomial?

A complex number polynomial is a polynomial function that has complex numbers as coefficients or variables. It can be written in the form of a + bi, where a and b are real numbers and i is the imaginary unit.

2. What does it mean for a complex number polynomial to have no root?

If a complex number polynomial has no root, it means that there is no complex number that satisfies the polynomial equation. In other words, when the polynomial is set equal to 0, there is no value for the variable that makes the equation true.

3. Can a complex number polynomial have no roots?

Yes, a complex number polynomial can have no roots. Just like real number polynomials, not all complex number polynomials have roots. It depends on the coefficients and the degree of the polynomial.

4. How can I determine if a complex number polynomial has no root?

To determine if a complex number polynomial has no root, you can use the Fundamental Theorem of Algebra. This theorem states that a polynomial of degree n has exactly n complex roots, counting multiplicities. So if the degree of the polynomial is greater than the number of complex roots, then the polynomial has no root.

5. What is the significance of a complex number polynomial with no root?

A complex number polynomial with no root has no solutions in the complex plane, and therefore cannot be factored into linear factors with complex coefficients. This could be significant in certain applications or problems that involve polynomial equations, as it limits the possible solutions to real numbers only.

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