JEE Main201910 Jan 2019Evening ShiftMathematicsComplex NumberActual
Let z = 3 2 + i 2 5 + 3 2 - i 2 5 . If R z and I z respectively denote the real and imaginary parts of z , then
Options
- AI z = 0
- BR z < 0 and I z > 0
- CR z > 0 and I z > 0
- DR z = - 3
Correct answer
A. I z = 0
Step-by-step solution
Let α = 3 2 + i 2 , then z = α 5 + α ¯ 5   We know z ¯ n = z ¯ n   , then, z = 2 R e α 5   Hence, I z = 0 .