Quadratic equation with complex coefficients

In summary, the conversation discusses solving a quadratic equation with complex numbers. One person suggests using polar coordinates to eliminate the square root, while another suggests using the method of letting z = a + b.i. The conversation concludes with simplifying the complex number and solving the equation.
  • #1
elimenohpee
67
0

Homework Statement


Solve the quadratic equation

z^2 + 4(1 + i(3^0.5))z - 16 = 0


Homework Equations





The Attempt at a Solution


I think I've done this correctly, I just wanted to verify.
I've only done the solution for k=0

http://i129.photobucket.com/albums/p201/elimenohpee182/Capture-1.png
 
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  • #2
I'm interested to know, why did you use polar coordinates? Would it not be easier to let z = a + b.i, then solve for a and b?
 
  • #3
I thought using polar coordinates would be easiest to eliminate the square root of the complex number.

I don't know if its right or not, that's why I wanted someone to check it.
 
  • #4
You want to get rid of the square root of the determinant, so let [tex]\sqrt{-96+32i}=a+ib[/tex] on squaring both sides, we solve [tex]-96+32i=a^2-b^2+2abi[/tex]

Thus you have two equations to solve, [tex]-96=a^2-b^2[/tex] and [tex]32=2ab[/tex] since the real and imaginary coefficients must be equal.

But first you may want to check if you can simplify -96+32i. Notice 96=32*3
 

FAQ: Quadratic equation with complex coefficients

1. What is a quadratic equation with complex coefficients?

A quadratic equation with complex coefficients is an algebraic equation in the form of ax^2 + bx + c = 0, where a, b, and c are complex numbers. It is used to solve problems involving parabolas, such as finding the roots or solutions of a quadratic function.

2. How do you solve a quadratic equation with complex coefficients?

To solve a quadratic equation with complex coefficients, you can use the quadratic formula: x = (-b ± √(b^2 - 4ac)) / 2a. First, simplify the equation by combining like terms. Then, use the quadratic formula to find the solutions for x. If the discriminant (b^2 - 4ac) is negative, the solutions will be complex numbers.

3. What is the discriminant in a quadratic equation with complex coefficients?

The discriminant in a quadratic equation with complex coefficients is the value inside the square root of the quadratic formula: b^2 - 4ac. It helps determine the nature of the solutions of the equation. If the discriminant is positive, there will be two distinct real solutions. If it is zero, there will be one real solution. If it is negative, there will be two complex solutions.

4. Can a quadratic equation with complex coefficients have real solutions?

Yes, a quadratic equation with complex coefficients can have real solutions. This happens when the discriminant is zero, resulting in one real solution. An example of this is the equation x^2 + 2x + 1 = 0, which has a solution of x = -1.

5. Why do we use complex coefficients in quadratic equations?

Complex coefficients are used in quadratic equations to represent situations where the real number system is not enough. For example, in physics and engineering, complex numbers are often used to represent quantities like impedance and phase angle. Quadratic equations with complex coefficients are also important in understanding the behavior of parabolas in the complex plane.

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