Range of values in regards to quadratics and discriminant

  • Thread starter Thread starter ybhathena
  • Start date Start date
  • Tags Tags
    Range
AI Thread Summary
To determine the range of values for the constant a in the inequality ax^2 + 2ax + 3 ≥ 0, the discriminant must be analyzed. The correct discriminant is 4a^2 - 12a, which should be non-positive for the quadratic to have all real solutions. Setting the discriminant to zero gives critical points, leading to the conclusion that the range of a is 0 < a ≤ 3. This ensures that the quadratic does not cross the x-axis, maintaining non-negativity. Understanding the relationship between the discriminant and the quadratic's behavior is crucial for solving the problem.
ybhathena
Messages
42
Reaction score
0

Homework Statement



Determine the range of values of the constant a so that the solution of ax^2+2ax+3>=0 (when a >0) is all real numbers



Homework Equations



D = b^2-4ac


The Attempt at a Solution



The discriminant is 0, 3. I need to know how to arrange them to get the range. The range is 0<a<=3 in the answers. How do I get it?
 
Physics news on Phys.org
ybhathena said:

Homework Statement



Determine the range of values of the constant a so that the solution of ax^2+2ax+3>=0 (when a >0) is all real numbers



Homework Equations



D = b^2-4ac


The Attempt at a Solution



The discriminant is 0, 3.
No, the discriminant is 4a2 - 12a. What do your two values have to do with the discriminant? (I know, but I am trying to get you to be accurate in what you say.)
ybhathena said:
I need to know how to arrange them to get the range. The range is 0<a<=3 in the answers. How do I get it?
 
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Back
Top