Complex Variables (Finding complex roots)

In summary, the conversation is about finding all solutions to the equation (z^2+1)^2=-1. The conversation includes a discussion about the degree of the polynomial and how it relates to the solutions in the complex plane. One person suggests using factoring to find the solutions, while another person mentions that the solutions can be found by taking the square root of a complex number. The final solution is given as ±21/4*exp(i3\pi/8) and 21/4*exp(i5\pi/8).
  • #1
Polamaluisraw
21
0

Homework Statement


Find all solutions to (z2+1)2=-1


The Attempt at a Solution


I know that because it is a polynomial of degree 4 it is a square inscribed inside of a circle in the complex plane. All i really need is one solution and from that finding the other three is easy. I have tried factoring it numerous ways. the best I get it to is

z2= i -1

thank you!
 
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  • #2
Don't you get ##z^2=-1\pm i##? Do you know how to find the square roots of a complex number? That would give you your four roots.
 
  • #3
LCKurtz said:
Don't you get ##z^2=-1\pm i##? Do you know how to find the square roots of a complex number? That would give you your four roots.

wow i completely left of the ± that is my problem! Let me work it and ill report back, thank you!
 
  • #4
got it,

±21/4*exp(i3[itex]\pi[/itex]/8)
21/4*exp(i5[itex]\pi[/itex]/8)

thank you again
 

Related to Complex Variables (Finding complex roots)

1. What are complex numbers?

Complex numbers are numbers that have both a real and imaginary component. They are typically written in the form a + bi, where a is the real part and bi is the imaginary part (with i representing the square root of -1).

2. How do you find the complex roots of a quadratic equation?

To find the complex roots of a quadratic equation, you can use the quadratic formula: x = (-b ± √(b^2 - 4ac)) / 2a. This formula will give you two complex solutions for x, which represent the two roots of the equation.

3. Can complex roots be irrational?

Yes, complex roots can be irrational. In fact, they are often irrational since the square root of a negative number is typically irrational.

4. How do you graph complex numbers?

Complex numbers can be graphed on a coordinate plane called the complex plane. The real component is plotted on the horizontal axis and the imaginary component is plotted on the vertical axis. The point where the two components intersect represents the complex number on the plane.

5. What is the purpose of finding complex roots?

Finding complex roots can be useful in solving various mathematical problems, such as finding solutions to quadratic equations or analyzing the behavior of complex systems. They also have applications in fields such as engineering, physics, and economics.

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