Animated Solution for Mathematics - Complex Numbers: Let α and β be the sum and the product of all the non-zero solutions of the equation (zˉ)2+∣z∣=0,z∈C. Then 4(α2+β2) is equal to :
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Visualized Solution
Defining z=x+iy
Let the complex number be z=x+iy, where x,y∈R.
The conjugate is zˉ=x−iy.
The modulus is ∣z∣=x2+y2.
Substituting into (zˉ)2+∣z∣=0
Original Equation: (zˉ)2+∣z∣=0
Substitute z and ∣z∣:
(x−iy)2+x2+y2=0
Expanding (x−iy)2
Expand (x−iy)2 using (a−b)2=a2−2ab+b2:
x2+(iy)2−2ixy+x2+y2=0
Since i2=−1:
x2−y2−2ixy+x2+y2=0
Separating Real and Imaginary Parts
Group real and imaginary terms:
(x2−y2+x2+y2)+i(−2xy)=0
Set Real part to zero: x2−y2+x2+y2=0
Set Imaginary part to zero: −2xy=0
Solving −2xy=0
From −2xy=0, we have two cases:
Case 1:x=0
Case 2:y=0
Case 1: x=0
Substitute x=0 into the Real part equation:
02−y2+02+y2=0
−y2+∣y∣=0
∣y∣−∣y∣2=0
Solutions for Case 1
Factorize: ∣y∣(1−∣y∣)=0
Possible values: ∣y∣=0 or ∣y∣=1
For non-zero solutions, ∣y∣=1⇒y=±1
Solutions: z=i and z=−i
Case 2: y=0
Substitute y=0 into the Real part equation:
x2−02+x2+02=0
x2+∣x∣=0
∣x∣2+∣x∣=0⇒∣x∣(∣x∣+1)=0
Analyzing Case 2
Since ∣x∣≥0, then ∣x∣+1≥1.
Thus, ∣x∣+1=0.
The only solution is ∣x∣=0⇒x=0.
This gives z=0, which is rejected (we need non-zero solutions).
Calculating Sum α and Product β
Non-zero solutions: z1=i,z2=−i
Sum α=i+(−i)=0
Product β=i⋅(−i)=−i2=1
Final Evaluation
Expression to evaluate: 4(α2+β2)
Substitute α=0 and β=1:
4(02+12)=4(1)=4
The final value is 4.
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The Sigma Insight: Algebraic Operations on Complex Numbers
Solution Diagram
The Geometry of Complex Equations
Welcome, fellow explorer of the complex plane! Today, we are going to dismantle a beautiful problem that might look intimidating at first glance, but reveals a stunning symmetry once we peel back the layers.
We are dealing with the equation (zˉ)2+∣z∣=0. At first, it looks like a jumble of conjugates and moduli, but we are going to use the most reliable tool in our JEE arsenal: the Cartesian representation.
The Cartesian Foundation
Whenever you see an equation involving z, zˉ, and ∣z∣, do not panic. The safest, most systematic approach is to define z=x+iy, where x and y are real numbers.
This immediately gives us the conjugate zˉ=x−iy and the modulus ∣z∣=x2+y2. By substituting these into our original equation, we transform a complex-variable problem into a system of real-variable equations.
The Expansion and the Trap
Let us substitute our definitions into the equation:
(x−iy)2+x2+y2=0
Now, we expand the squared term. Since (x−iy)2=x2−y2−2ixy, our equation becomes:
x2−y2−2ixy+x2+y2=0
We group the real and imaginary parts:
(x2−y2+x2+y2)+i(−2xy)=0
For this complex number to be zero, both the real part and the imaginary part must vanish independently. This gives us two crucial equations:
x2−y2+x2+y2=0
−2xy=0
The Bifurcation of Cases
Look at the imaginary part: −2xy=0. This is a gift! It tells us that either x=0 or y=0.
Case 1: x=0
Substituting this into our real part equation, we get −y2+y2=0. Since y2=∣y∣, we have ∣y∣−∣y∣2=0.
Factoring this, we get ∣y∣(1−∣y∣)=0. This gives us ∣y∣=0 (which leads to z=0) or ∣y∣=1. Thus, y=±1, yielding non-zero solutions z=i and z=−i.
Case 2: y=0
Substituting this into the real part equation, we get x2+x2=0, which simplifies to ∣x∣2+∣x∣=0. Since ∣x∣≥0, the only solution is ∣x∣=0, which leads to z=0. We reject this as it is not a non-zero solution.
The Final Victory
We have found our non-zero solutions: z1=i and z2=−i. The problem asks for the sum α and the product β of these solutions.
The sum α=i+(−i)=0. The product β=i⋅(−i)=−i2=1.
Finally, we evaluate the expression 4(α2+β2):
4(02+12)=4(1)=4
We have arrived at the answer! The final result is 4.