Animated Solution for Mathematics - Complex Numbers: If α,β∈C are the distinct roots, of the equation x2−x+1=0, then α101+β107 is equal to :
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Visualized Solution
The Given Equation x2−x+1=0
Given equation: x2−x+1=0
Roots are α and β
We need to find: α101+β107
Finding the Roots using Quadratic Formula
Using quadratic formula: x=2a−b±b2−4ac
Substitute a=1,b=−1,c=1:
x=2(1)−(−1)±(−1)2−4(1)(1)
x=21±−3=21±i3
Identifying Roots as −ω and −ω2
Recall cube roots of unity: ω=2−1+i3 and ω2=2−1−i3
Our roots are:
21+i3=−(2−1−i3)=−ω2
21−i3=−(2−1+i3)=−ω
Assigning α and β
Let α=−ω
Let β=−ω2
Properties of ω: ω3=1 and 1+ω+ω2=0
Evaluating α101+β107
Substitute α and β:
α101+β107=(−ω)101+(−ω2)107
Simplifying α101=(−ω)101
(−ω)101=(−1)101⋅ω101
Since 101 is odd, (−1)101=−1
So, (−ω)101=−ω101
Reducing ω101 to ω2
Divide 101 by 3: 101=3×33+2
ω101=ω3×33⋅ω2
(ω3)33⋅ω2=(1)33⋅ω2=ω2
Therefore, α101=−ω2
Simplifying β107=(−ω2)107
(−ω2)107=(−1)107⋅(ω2)107
Since 107 is odd, (−1)107=−1
(−ω2)107=−ω2×107=−ω214
Reducing ω214 to ω
Divide 214 by 3: 214=3×71+1
ω214=ω3×71⋅ω1
(ω3)71⋅ω=(1)71⋅ω=ω
Therefore, β107=−ω
Substituting back into the Expression
α101+β107=−ω2+(−ω)
=−ω2−ω
=−(ω2+ω)
Applying the Identity 1+ω+ω2=0
Using identity: 1+ω+ω2=0
Rearranging gives: ω2+ω=−1
Final Result
Substitute −1 back:
−(ω2+ω)=−(−1)=1
Final Answer: 1
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The Sigma Insight: Cube Roots and nth Roots of Unity
Solution Diagram
Analyzing the Quadratic Foundation
We begin with the given quadratic equation:
x2−x+1=0
Using the quadratic formula x=2a−b±b2−4ac, we substitute a=1, b=−1, and c=1. This yields:
x=21±1−4=21±i3
These values represent our roots, α and β. They are not merely random complex numbers; they are intrinsically linked to the cube roots of unity.
The Bridge to Unity
Recall the definition of the complex cube roots of unity, where ω=2−1+i3 and ω2=2−1−i3. If you examine our roots 21±i3 closely, you will notice they are exactly −ω2 and −ω.
This identification is the critical "Aha!" moment. By recognizing our roots as −ω and −ω2, we unlock the two fundamental properties of ω:
ω3=1
1+ω+ω2=0
The Power Reduction
Now, we address the expression α101+β107. Substituting our identified values, we obtain:
(−ω)101+(−ω2)107
Because 101 and 107 are odd, the negative signs persist, resulting in:
−ω101−ω214
We now apply the property ω3=1 by dividing the exponents by 3. For the first term, 101=3×33+2, so ω101=ω2. For the second term, 214=3×71+1, so ω214=ω.
The Elegant Conclusion
Our expression simplifies to:
−(ω2+ω)
Recalling our second property, 1+ω+ω2=0, we know that ω2+ω=−1. Substituting this into our expression, we get:
−(−1)=1
The massive powers have vanished, leaving behind a simple, beautiful integer. The final result is 1.