Animated Solution for Mathematics - Quadratic Equations: Let a∈R and let α,β be the roots of the equation x2+6041x+a=0. If α4+β4=−30, then the product of all possible values of a is
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Visualized Solution
Given Equation and Condition
Given equation: x2+6041x+a=0
Roots: α,β
Given condition: α4+β4=−30
Vieta's Formulas
Sum of roots: α+β=−6041
Product of roots: αβ=a
Identity for α2+β2
α2+β2=(α+β)2−2αβ
Substitute into α2+β2
α2+β2=(−6041)2−2a
Simplify α2+β2
α2+β2=6042−2a
α2+β2=60−2a
Identity for α4+β4
α4+β4=(α2+β2)2−2(αβ)2
Form the Equation
(60−2a)2−2a2=−30
Expand the Square
(60)2−2(60)(2a)+(2a)2−2a2=−30
60−4a60+4a2−2a2=−30
Simplify and Group
60−4a(215)+2a2=−30
2a2−815a+60=−30
Quadratic in a
2a2−815a+60+30=0
2a2−815a+90=0
Product of Roots for a
Product of values of a=Coefficient of a2Constant term
Product =290
Final Calculation
Product of all possible values of a=45
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The Sigma Insight: Relation Between Roots and Coefficients
Analyzing the Setup
Imagine you are standing before a seemingly daunting algebraic challenge. You are given a quadratic equation, x2+6041x+a=0, and told that its roots, α and β, satisfy a mysterious condition: α4+β4=−30.
At first glance, this looks like a problem that might require finding the roots themselves. But as an elite student, you know better. The secret to solving this lies not in finding the roots, but in understanding their collective behavior.
The Vieta's Foundation
Whenever we deal with the roots of a polynomial, our first instinct should be to invoke Vieta's formulas. They are the bridge between the roots and the coefficients.
For our equation, the sum and product of the roots are:
α+β=−6041
αβ=a
This is our toolkit. We do not need to know what α or β are individually; we only need their sum and product to unlock the higher powers.
The Recursive Identity Strategy
We need to reach α4+β4. We build it up, step by step, starting with the sum of squares:
α2+β2=(α+β)2−2αβ
Substituting our known values, we get α2+β2=(−6041)2−2a. Simplifying this, the negative sign vanishes, and the power becomes 6042, which is simply 60.
Thus, we have:
α2+β2=60−2a
Now, we take the next leap. We use the same identity structure for the fourth powers:
α4+β4=(α2+β2)2−2(αβ)2
This is where the magic happens. We have successfully reduced a fourth-degree problem into a simple quadratic expression in terms of a.
The Algebraic Expansion
Let us substitute our expression for the sum of squares into the identity:
(60−2a)2−2a2=−30
Expanding the square of (60−2a), we obtain 60−4a60+4a2. Subtracting 2a2, we get:
60−4a60+2a2=−30
Simplifying 60 as 215, the term 4a60 becomes 8a15. Our equation now stands as:
2a2−815a+60=−30
Bringing the −30 to the left, we arrive at the final quadratic:
2a2−815a+90=0
Final Calculation
The problem asks for the product of all possible values of a. The values of a that satisfy the condition are the roots of the quadratic equation 2a2−815a+90=0.
We do not need to solve for a using the quadratic formula. We simply use Vieta's formula for the product of the roots:
Product=Coefficient of a2Constant term=290=45
And there it is. The complexity dissolves into a simple, elegant result. By trusting the identities and avoiding the trap of calculating the roots directly, we have conquered the problem.