JEE Main20209 Jan 2020Morning ShiftMathematicsComplex NumberActual

Let z be a complex number such that z - i z + 2 i = 1 and z = 5 2 . Then, the value of z + 3 i is

Options

A10
B7 2
C15 4
D2 3

Correct answer

B. 7 2

Step-by-step solution

Given, z - i = z + 2 i ⇒ x 2 + y - 1 2 = x 2 + y + 2 2 ⇒ - 2 y + 1 = 4 y + 4 ⇒ 6 y = - 3 ⇒ y = - 1 2 From, z = 5 2 , we get, x 2 + y 2 = 25 4 ⇒ x 2 = 24 4 = 6 ⇒ z = ± 6 - i 2 Hence, z + 3 i = 6 + 25 4 = 49 4 z + 3 i = 7 2

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: 2026 Let S = z C : z^2 + 6 ,iz - 3 = 0 . Then _ z S z^8 is equal to : 2026 Let 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: 2026 Let z₁, z₂ C be the distinct solutions of the equation z^2 + 4z - (1 + 12i) = 0 . Then |z₁|^2 + |z₂|^2 is equal to : 2026 Let S= z C : z^2+4z+16=0 . Then _ z S |z+ 3 i|^2 is equal to: 2026 Let z be a complex number such that |z+2| = |z-2| and ( z+3 z-i ) = 4 . Then |z|^2 is equal to: 2026 Let 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: 2026 Let 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