JEE Main · Mathematics ↓ Falling

Complex Numbers appeared 41 times across 3 years — 4.7% of Mathematics. This question is from Complex Equations and Modulus.

Year 2026 2025 2024 Total
Questions 11 16 14 41

Let S = z in C : 4z² + z = 0. Then Σz in S |z|² is equal to:

Solution & Explanation

Related Formula

For z = x + iy, z = x - iy and |z|² = x² + y².

Core Logic

Substitute z = x + iy into 4z² + z = 0:

4(x² - y² + 2ixy) + x - iy = 0

Separating real and imaginary parts:

4x² - 4y² + x = 0 and y(8x - 1) = 0

Case 1: y = 0 4x² + x = 0 x = 0 or x = -1/4. Solutions: z₁ = 0 |z₁|² = 0, z₂ = -1/4 |z₂|² = 1/16.

Case 2: x = 1/8 4(1/64) - 4y² + 1/8 = 0 4y² = 3/16 y = ± √(3)8. Solutions: z₃, z₄ = (1)/(8) ± i √(3)8 |z₃|² = |z₄|² = (1)/(64) + (3)/(64) = (1)/(16).

Step 1: Sum of Modulus Squared
Σz in S |z|² = 0 + (1)/(16) + (1)/(16) + (1)/(16) = (3)/(16)
Pattern Recognition

Separate complex equation into real and imaginary components to systematically find all roots.

Chapter Mix

Class 11 Maths: Complex Numbers

Reference Study Guides

More Complex Numbers Previous-Year Questions — Page 9

Q26 jee_main_2024_31_jan_morning Properties of Modulus and Argument
If α denotes the number of solutions of |1 - i|^x = 2^x and β = ((|z|)/( (z))), where z = (π)/(4) (1 + i)⁴ ( 1 - √(π) i√(π) + i + √(π) - i1 + √(π) i), i = √(-1), then the distance of the point (α, β) from the line 4x - 3y = 7 is
Numerical Answer. Answer: 3 to 3

Solution

Core Logic
|1 - i|^x = 2^x (√(2))^x = 2^x 2x/2 = 2^x

This implies (x)/(2) = x x = 0. There is exactly 1 solution, so α = 1.

Step 1: Simplify complex number z
(1+i)⁴ = ((1+i)²)² = (1 + i² + 2i)² = (2i)² = -4

Thus, z = -π ( (1-√(π)i)(√(π)-i)π + 1 + (√(π)-i)(1-√(π)i)1 + π )

Step 2: Simplify Bracket

Let's expand the terms directly: z = (π)/(4)(-4) [ √(π) - π i - i - √(π)π + 1 + √(π) - i - π i - √(π)1 + π ]

= -π [ (-i(π+1))/(π+1) + (-i(π+1))/(π+1) ] = -π [ -i - i ] = 2π i
Step 3: Find beta

For z = 2π i: |z| = 2π and (z) = (π)/(2).

β = (|z|)/( (z)) = (2π)/(π/2) = 4
Step 4: Distance from Line

Distance of point (α, β) = (1, 4) from the line 4x - 3y - 7 = 0:

D = |4(1) - 3(4) - 7|√(4² + (-3)²) = (|4 - 12 - 7|)/(5) = (|-15|)/(5) = 3
Chapter Mix

Class 11 Maths: Complex Numbers and Quadratic Equations Class 11 Maths: Straight Lines

More Complex Numbers Questions — jee_main_2026_22_january_evening

Practice all Complex Numbers previous-year questions →

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