Quadratic Equation with three variables

In summary, if a quadratic equation of two variables represents a conic section, then a quadratic equation of three variables can represent the complete cone. This is known as a second-degree equation and can represent various quadric surfaces, including spheres, ellipsoids, paraboloids, hyperboloids, cones, and degenerate surfaces. It is recommended to do some basic research before posting questions and to post them in the appropriate section.
  • #1
Leo Authersh
If a quadratic equation of two variables represents a conic section (planar intersection of a cone), then does a quadratic equation of three variables represent the complete cone?

@fresh_42 @FactChecker @WWGD
 
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  • #2
If you have 3 independent variables, is it still a quadratic equation?
 
  • #4
Leo Authersh said:
If a quadratic equation of two variables represents a conic section (planar intersection of a cone), then does a quadratic equation of three variables represent the complete cone?
No.
The usual terminology is second-degree equation. As already mentioned, a second-degree equation in three variables represents a quadric surface, including spheres, ellipsoids, paraboloids, hyperboloids, cones, and a few other degenerate surfaces (the equation ##x^2 + y^2 + z^2 = 0## represents a single point at the origin.)

@Leo Authersh, please do a little basic research before posting your questions. Also, I have moved several of your threads to the General Math section. They are not questions that pertain to Topology or Analysis.
 
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1. What is a quadratic equation with three variables?

A quadratic equation with three variables is a polynomial equation that contains three variables, typically represented as x, y, and z. It is expressed in the form of ax2 + bx + cy + d = 0, where a, b, and c are constants and x, y, and z are variables.

2. How is a quadratic equation with three variables solved?

A quadratic equation with three variables can be solved using various methods such as substitution, elimination, or graphical methods. The most common method is the substitution method, where one variable is solved in terms of the other and substituted into the equation to solve for the remaining variable.

3. What are the real solutions of a quadratic equation with three variables?

A quadratic equation with three variables can have either one or two real solutions, depending on the values of the variables and constants. If the discriminant (b2 - 4ac) is positive, then the equation will have two real solutions. If the discriminant is zero, the equation will have one real solution. If the discriminant is negative, the equation will have no real solutions.

4. Can a quadratic equation with three variables have complex solutions?

Yes, a quadratic equation with three variables can have complex solutions. If the discriminant is negative, the equation will have two complex solutions in the form of a + bi, where a and b are real numbers and i is the imaginary unit.

5. How are quadratic equations with three variables used in real life?

Quadratic equations with three variables are used in various fields such as physics, engineering, and economics to model and solve real-life problems. For example, they can be used to calculate the maximum or minimum value of a function, determine the trajectory of a projectile, or analyze the cost and revenue of a business.

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