Maths - a proof question on the nature of roots of quadratic equations

In summary, the question is asking to prove that the inequality s^{2} -4s - 12 ≥ 0 is true for any real value of x, given that s =\frac{4(x^{2}) + 3}{2x-1}. To do this, we can rewrite the given equation in terms of x and then use the discriminant rule b^2 - 4ac ≥ 0 to determine if the inequality is true.
  • #1
Eutrophicati
10
0
I'm sorry, I just realized I put this in the wrong subsection. While I figure out how to fix that, please have a look anyway.
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Homework Statement



Given x [itex]\inℝ[/itex]
And s =[itex]\frac{4(x^{2}) + 3}{2x-1}[/itex]
Prove that [itex]s^{2}[/itex] -4s - 12 ≥ 0

Homework Equations


The discriminant Δ, (in order for which to be real must be ≥ 0)
b^2 - 4ac ≥ 0

The Attempt at a Solution


Doing the algebra isn't the problem, I'm having trouble understanding the question itself. For this sort of proof, don't I need to work with
s =[itex]\frac{4(x^{2}) + 3}{2x-1}[/itex]
instead of the statement to be proven, which is [itex]s^{2}[/itex] -4s - 12 ≥ 0?

In which case, how do I apply the b^2 - 4ac rule with the linear equation part in the denominator?
 
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  • #2
The variable is ##x##, so make the given equation look like a regular quadratic in ##x##. Then pick off what ##a##, ##b##, and ##c## are and write the inequality for ##\Delta## in terms of those. It will quickly resolve into what's requested.
 

1. What is a quadratic equation?

A quadratic equation is an equation that can be written in the form ax^2 + bx + c = 0, where a, b, and c are constants and x is the variable. It is a polynomial equation of degree 2.

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

The roots of a quadratic equation can be found using the quadratic formula, which is (-b ± sqrt(b^2 - 4ac)) / 2a. Alternatively, you can also factor the equation and solve for the roots.

3. What is the nature of the roots of a quadratic equation?

The nature of the roots of a quadratic equation depends on the value of the discriminant, which is b^2 - 4ac. If the discriminant is positive, the equation will have two distinct real roots. If the discriminant is zero, the equation will have one real root (which is also known as a double root). If the discriminant is negative, the equation will have two complex roots.

4. Can a quadratic equation have no real roots?

Yes, a quadratic equation can have no real roots if the discriminant is negative. In this case, the roots will be complex numbers.

5. Why is it important to prove the nature of roots of a quadratic equation?

Proving the nature of roots of a quadratic equation is important because it helps us understand the behavior and solutions of the equation. It also allows us to determine the number and type of solutions without having to solve the equation.

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