Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main2014MathematicsComplex NumberActual

For all complex numbers z of the form 1 + i α , α ∈ R , if z 2 = x + i y , then

Options

  1. Ay 2 - 4 x + 4 = 0
  2. By 2 + 4 x - 4 = 0
  3. Cy 2 - 4 x + 2 = 0
  4. Dy 2 + 4 x + 2 = 0

Correct answer

B. y 2 + 4 x - 4 = 0

Step-by-step solution

Given z = 1 + iα ,   z 2 = x + iy ⇒ 1 + iα 2 = x + iy ⇒ 1 2 + i 2 α 2 + 2 i α = x + i y Using i 2 = - 1 , ⇒ 1 - α 2 + 2 i α = x + iy Equating the real and imaginary parts, we get x = 1 - α 2 and y = 2 α ⇒ α 2 = 1 - x and y 2 = 4 α 2 ⇒ y 2 = 4 1 - x ⇒ y 2 = 4 - 4 x ⇒ y 2 + 4 x - 4 = 0 .

Practice Complex Number on Quantrex Academy →

More from Complex Number

The number of values of z C , satisfying the equations |z-(4+8i)|= 10 and |z-(3+5i)|+|z-(5+11i)|=4 5 , is: 2026Let S = z C : z^2 + 6 ,iz - 3 = 0 . Then _ z S z^8 is equal to : 2026Let the set of all values of k R such that the equation z( z + 2 + i) + k(2 + 3i) = 0 , z C , has at least one solution, be the interval [ , ] . Then 9( + ) is equal to: 2026Let z₁, z₂ C be the distinct solutions of the equation z^2 + 4z - (1 + 12i) = 0 . Then |z₁|^2 + |z₂|^2 is equal to : 2026Let S= z C : z^2+4z+16=0 . Then _ z S |z+ 3 i|^2 is equal to: 2026Let z be a complex number such that |z+2| = |z-2| and ( z+3 z-i ) = 4 . Then |z|^2 is equal to: 2026Let the circles C₁ : |z| = r and C₂ : |z - 3 - 4i| = 5 , z C , be such that C₂ lies within C₁ . If z₁ moves on C₁ , z₂ moves on C₂ and |z₁ - z₂| = 2 , then |z₁ - z₂| is equal to: 2026Let x and y be real numbers such that 50 ( 2x 1+3i - y 1-2i ) = 31 + 17i , i = -1 . Then the value of 10(x - 3y) is : 2026 Full Complex Number list All JEE Main PYQs